This article may have points you hadn’t considered.

https://jillianlare.com/living-in-place-bathroom-design/

A zillion articles on here covering what you need to know (including sinks):

https://www.houzz.com/ideabooks/query/universal-design-bathroom/nqrwns

The UD code, if you want some light reading:

https://code.universaldesign.org/chapter/bathrooms

We built our theoretically-forever home incorporating a lot of the UD principles for aging in place. You need to think not just about the bathroom but EVERYWHERE in the house - the width of hallways and doorways throughout (inc the front door), senior-safe flooring, extra lighting, and so on.

As an older person I like having counter space to put thins on for personal grooming. There are vanities designed to accommodate a wheelchair but that section is lower than the rest of countertop height. As far as the, no slip porcelain is the way to go, built in bench and a grab bar on each wall. Make certain the shower controls are easily accessible without having to step into the shower. You are great people to do this for your MIL.

Thanks for the advice. We had already incorporated a lot of the suggested things but there were issues I hadn’t thought about such type of faucet handles and placement of the shower controls.

We had already planned for a curbless shower with bench and handheld sprayer. The toilet will have a pony wall on either side to mount gab bars. The contractor suggested switching out the door between her bedroom and the bathroom with a wider pocket door to eliminate the door swing. We’re looking at either a wall mounted or pedestal sink and an armoire or dresser for storage. We plan to reinforce the back wall for future grab bars.

The contractor needs to be done by March since he has already scheduled a huge job for then. I plan to order only in stock items.

Once I get a space plan from him I’ll post it for feedback.

We have a studio apartment down the hall from our main apartment and wanted to make it a comfortable and safe place for my aging parents to spend lengthy amounts of time in and live in if ever needed. I learned a ton a long the way from my father (an engineer who did lots of public building design including ADA), an OT we hired who specializes in aging in place home design, and from reading a ton online.

* ADA requirements are not actually what you want to use in a home. (Dad + OT agreed.) ADA standards are made for the general public and are created to accommodate the average person. Your home should be made to accommodate your loved one. Have your mother-in-law reach out and see where *her* arm goes to grab for stability, balance, and coming to standing. Base things on *her* height. I had my mom and dad test a lot of arm reaches and positions to see what would be comfortable for *them* to grab.

* Only 7% of older adults become wheelchair bound. Is there something in particular that indicates that your mother-in-law is going to be destined for a wheelchair? If not, the much more important things to focus on are:

1. Balance and stability - as those are issues that so many adults have - a long countertop is useful for this, not having to step to different locations to reach for cosmetics, toiletries, being able to set things on a counter if an action needs to gets broken down into many parts. Yes, a short sink is helpful if she is in a wheelchair but if she is the other 93% of the population, having a taller sink is better so she doesn't have to bend down so far to use it.

2. How to move around the space with two people in it - if she ever needs assistance with grooming or on the toilet - I'd never put pony walls on two sides of a toilet as you then cannot stand by her side if she needs help. Have a grab bar on one side. If she ends up needing one on the second side, install one that can hinge up and down from the wall as needed.

3. Reducing fall risks - Make sure floor surfaces have a high anti-slip rating - don't just rely on the adage that grout on mosaic tile will do enough to reduce slipping; Don't use grab bars that double as towel rods - cause of lots of accidents, use grab bars for balance and hooks for towels; Make a very good lighting design so there are no shadows, the room is well lit, it is easy and logical where to turn on the lights (remember no electric and plumbing in a pocket door wall); add plenty of outlets so you don't have to move around the room a lot to plug something in; have a place to sit down and dry off.

4. Make open floor space for a walker to live while she is on the toilet or in the shower. (Twice as many people use walkers as use wheelchairs and way more than that use canes.)

Wonderful that you are doing this. I cared for my father-in-law for many years and loved him as I do my own father. I get it! He had dementia and needs so much help but was never in a wheelchair. Went from walking to bed bound. Same was with my two uncles with parkinsons, walking to bedbound. My grandmother used a wheel chair for two weeks. We made do without wheelchair accessible accomodations.

Oh, a few other thoughts:

I learned a lot about grab bar placement too. Post a simple sketch of where you intend to mount grab bars - now or in the future.

Light switches - get rockers instead of toggles.

Chunky items are easier to grasp than slender ones when you have arthritis - knobs, bars, handles, if you have a choice between skinny or fatter, get fatter.

When you get older, sometimes the urgency to go comes on quite quickly. Closing a pocket door can take more dexterity and time, whereas throwing a door closed can be accomplished easily. Ask her - is she the kind to go with the door open or would she always close it! If you decide to have a swing door instead of pocket, have it open out instead of in to the bathroom. If she were ever to fall in the bathroom and block the door she could become trapped inside. Yes, my dad confessed to me this is one of his greatest fears about aging!

If she ever needs incontinence supplies they can take up a LOT of cabinet space. Here's to a vanity instead of pedestal. Here's to room for a larger trash can too!

Consider a bidet seat. I'd put the grab bars in now.

I actually think as close to real ADA requirements as possible is the way to go those guidelines are great when thinking about aging in place . I am thnkfully close to 80 but very fit and healthy but who knows what might happen. The bathrooms need to be large for ADA and that is the first thing needed to be figured out in most homes .. Grab bars a must and I garee figure those out for the person you are doing this for . all of those need to be figured out before installing anything . There is lots of info on the net regarding the ADA rules and IMO follow those closely

The bathroom is quite long but not very wide.

How wide is it?