You will want to measure the doorway the night the chair arrives, and you will be tempted to measure the door. Do not. The door is a slab of wood. The chair needs the open space the door leaves behind, and that space is smaller than the door in most houses, because of the frame, the trim, the stop the door closes against, and the hinge side.
Local option: New Plan Care gives families in the St. Louis area in-home help so a parent can stay home: companionship, help with bathing and dressing, meals, and overnight care. Call (314) 405-0887.
Measure the clear opening, not the door
Open the door fully, then find the narrowest point the chair has to pass through. It is usually the latch side at the stop, or the hinge side where the open door sits against the frame. Measure straight across from one side of the frame to the other, at the height where the wheels and the widest part of the chair will pass. Do this at the bottom, the middle, and the top of the opening, because trim and thresholds can narrow it at one spot only. Write each number down with the place you measured it.
Then measure the chair as it is actually set up: the widest point with the armrests, footrests, and wheels in their normal position, plus the seat cushion if it adds width. Ask the equipment company or the person who set up the chair for its overall width in writing. Do not rely on a number you remember from a catalog. A footrest that swings out or a folding part can change the answer.
Check the turn, not only the straight line
A doorway the chair fits through head on can still fail at the turn. Stand in the hall outside the room and mark where the chair has to turn to face the opening. If the hall is narrow, the chair may need a small turn at the threshold or a back-in approach. Test it with a cardboard sheet cut to the chair's footprint, or with the chair itself if it is already in the house. Watch the pushing side too. The person behind the chair needs room to stand and steer, not only room in front of the wheels.
Check the threshold and the floor
A small lip can stop a chair cold even when the width is fine. Look for threshold strips, rugs with raised edges, and changes in floor height between rooms. Note what has to be removed, moved, or changed before the chair arrives. Ask whoever advises on the setup whether a threshold ramp or a rug change is needed, and settle in advance who will buy it and who will install it.
Write the answer down before the furniture moves
Before you reorganize a room or order a new piece, write three lines: the narrowest opening, the chair's width as set up, and whether the turn works. If the numbers are close, do not guess. Ask the therapist, the equipment supplier, or the installer to confirm the fit in writing. If the house does not fit the chair you have, you want to learn that early, while there is still room to discuss a different chair, a different room for the bed, or a plan for the hard days.
If you need a place to start looking for help with the install or a referral, Local Help for Caregivers in St. Louis is where to begin.
You are not failing at the house. You are finding out which problem you have while it is still small.