This is something many people are facing, either for themselves or for older parents/ relatives. Trouble is, unless there is a bathroom on the same floor, you will have issues with hygiene. An alternative is to install an electric chair up a stairway to for access.

i always advocate an electric lift over reconfiguring public living space. my in-laws didnt for her mother... it would have made 5 years of their lives so much nicer if they had just put in the lift.