You want grab bars. A grab bar next to the toilet. One by the shower. You also want a shower big enough for a stool or a bench. You do need a handheld shower so if they want to shower sitting down on the bench/stool, they can do so. You want enough room around the toilet for one of those frames that provides arms that they can use to push up on.

Thankyou Ingrid. Great suggestions

There are also different toilet heights. They may want one with a higher seat level. And not a furniture-legs style vanity; it is harder to clean underneath.

Good lighting. Non-slip flooring. Grab bars in the shower and for holding when exiting the shower with wet feet. No toilet room unless it's big enough for a helper to move freely to assist with toileting. A bidet. Spacious enough for move around unimpeded (as if you have a yard stick at your waist). Look up CAPS design and AARP HomeFit guide.

Make doors and hallways for wider.

I had the door open out. If someone falls down in front of the doordoor, the door can still be opened.

My advice is go on google and read all the rules for ADA compliant bathrooms and things to do in the home to also be compliant. Bathrooms are a huge issue since they need to be large for wheelchairs or even walkers . I always prefer a bathroom door to open out for sure. You need to go online find the site for ADA design and then find a builder or contractor that specializes in this type of construction Kitchens are the other real issue to be workable . We all hope we will not be in a wheelchair but the fact is it can happen to anyone . Since this will be a new build it is great since you can design the whole thing to be right

I designed this for a customer it's a bedroom addition with a bathroom that will have wheelchair access in mind for the future with a 5 FT wheelchair turning radius.

They plan to have regular vanities for the time being but if a wheelchair is ever needed, they will change the vanity to a roll-under vanity for wheelchair access.

Here is something to give you an idea of the layout

I would strongly suggest you post the layout for the new home and include all of it. Particularly the entire primary bedroom suite, to include the bed, bath, closets all.

Nothing lives in isolation, so for the best advice? Post the framing plan in entirety of the "new forever home": )

Not elevations, the flat on paper , 2 dimension drawing WITH all the dimensions.

Don't read the ADA stuff, read the universal design stuff. There's some good articles on it here.

We built our primary bath in our theoretical forever home to accommodate for a wheelchair down the road. 36" door openings, 5' turning radius near the toilet, wall blocking for future grab bars near toilet & in/around shower, a bidet, no tile (we used micro-concrete instead), no door on the shower (very controversial on this forum lol), no-curb entry into bathroom and into shower, handheld as well as wall-mounted showerheads & flip-up shower bench seating. The one thing we didn't do (but can change later) is a vanity that can accommodate a wheelchair rolling underneath it.

Also, multiple lighting sources with dimmers, single-handle (lever) sink & shower water controls, drawers instead of doors in vanities. That's most of it, anyway. Helped that we had a large space to do it in (11x16ish).