Considering Your need for bathroom remodeling, for the older person with wheelchair, I’ m offering you one idea with two solutions.
For proper space accessibility it is necessary to put wider door: around 3 feet because wheelchair is 2,5 feet. Door has to be sliding or should open outside of the bathroom. I prefer sliding door because it is much easier to use them from wheelchair. Doorstep must be on floor level.
Existing bathtub is removed from the bathroom. Instead of it `shower space is designed on the floor level, with two liner 30 inch shower drains. Both, shower curtain and drains are preventing water from spreading all over the bathroom. Shower is placed on the right side of the wall beside window and the wall mounted shower seat is on the wall nearby. The seat can be opened or closed depending of the need. Closed seat provides necessary space for rotating wheelchair and using toilet. Unfortunately, there is no place in the bathroom for walk in bathtub for senior. Its minimal dimensions are 30x52 inch. Also necessary circle of five feet open space for wheelchair turning around would not be able to achieve in this small bathroom.
All bathroom safety bars are included where it’s necessary: around shower, toilet and bathroom sink. There are various safety bars on USA market. In the model I have shown some of them such as: fixed and flip down grab bars, but there are many bars combined with toilet paper holder, towel holder, etc.
In solution Nr. 1 bathroom sink is on the same place, and must be wall-mounted. Water and drainage fixtures are the same. The wall near bathroom sink has to be removed because the dimensions of the bathroom are small and each inch of the open space in the bathroom for the wheelchair: five feet open space is necessary for turning around and placing near bathroom equipment. Toilet bowl is below window and shifted a little bit from the wall enabling the use of safety bars. Fixtures are new, this part of the bathroom demands their replacing (removing bathtub) anyway.
Window needs glass protection such as: sand glass or non transparent foils.
The difference between solutions No 1 and 2 is toilet bowl and bathroom sink replacement. Water and drainage fixtures in the whole bathroom have to be changed. The main idea in bathroom planning is to hide toilet, not to be in seen directly when you enter the bathroom and lavatory near window is better because of the light. Therefore this solution is also fine.
Both solutions are designed according to ADA standards for accessible design from 2010, for public buildings.