You will need to have a pro come to see where the water gets in . The one pic looks like there is no sheathing or siding on that part of the house. Is there gutters and downspouts to divert rain We need a lot more pictures of the exterior for sure.

You need a pro to come on site and take a look. One picture shows daylight coming through the wall. Another shows a block wall - is that below grade? You potentially have a lot going. Before the clean up was there any indication on where the water was entering - or you are thinking this was a one time flood incident and not general seepage all year?

one of my past houses had awful water issues in the basement. the previous owner even installed a french drain.

when we moved in someone suggested that we build up and add mulch on all outside walls.

my hubs and I paid to have a truck load of dirt and a truck load of mulch dropped off and got to work. after the beds were in place we had fun shopping at a nursery and added plants and flowers.

that did the trick and the basement never got water again!

It does not look like there is any wrapping before the T111 was applied. You can see daylight.

Have a professional come in.

Also, need to look at the way water drains around the exterior. You may need to put in ground drainage to move water away from the base of the structure. Hard to tell from the pics. Need pics that are exterior from a short distance.

Well, that's really obvious (besides seeing daylight). You have cheap T-111 siding installed with no vapor barrier/tar paper, etc. underneath it.

That all has to come off, and the wall made waterproof under the siding. Then, the T-111 (if you use it again) has to be installed properly and protected from the weather. You can see the decay above the Z-flashing from water not draining properly. That kind of joint needs protection from the elements--a roof that projects far enough. As a practical matter, T-111 is not a permanent siding.

Side the house properly with plywood or OSB, then house wrap, then an impervious siding on top (vinyl/Hardie, etc.). There are plenty of articles and drawings on the web of the right way to side a house.

And make sure the sill is high enough off the ground (especially if you get snow), and that the joint between the foundation and sill is weatherproofed on the outside.

Your contractor should know how to do it properly. If not, fire him.

Good advice. Unless it is a broken pipe, water problems start on the outside.

See what you can do about grading. Do not have any grade above the foundation. Waterproof the outside below grade block walls.

Install 5 inch gutters and leaders (make sure they are always clean) that take any runoff away from the house.

Use insulation that is not porous.

In the last photo it appears that the bottom edge of the siding is at or near grade?

In the next to last photo, it looks like the bottom plate of the wall on the left is below the level of the really rough concrete floor.

Given that the T111 has been patched twice in the past, there has been an ongoing battle vs water.

Is this guest suite a converted carport or open air pool house?