You do not need to do this at night, and you should not try. Pick a daylight hour when the bathroom is free and nobody needs the tub for a few hours. The strips are simple, but the surface has to be right before the first one goes down, and the rushed version is the one that lifts at the edges by the next week.
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.
Before you open the box
Read the package for the tub surface it is made for. Tubs come in different finishes, and the directions are written for specific ones. If your tub's finish is not listed, or you are not sure what it is, check the manufacturer's written directions or ask the seller before you buy more. Set out the strips, a roll of painter's tape, a bucket of warm water with mild soap, a clean cloth, a dry towel, and a tape measure where you can reach all of them without stepping into the tub.
Clean the tub floor, then let it dry longer than you think
Scrub the floor of the tub with the soapy water, rinse it, and wipe it with a clean cloth. Soap film is the usual reason strips fail, and you cannot see it. After the rinse, dry the floor with the towel, then leave the room open for a while so the surface is fully dry before any strip touches it. Moisture under a strip holds it up at the edges.
Plan where her feet go
Strips do not need to cover the whole floor. Cover the places her feet land: where she steps over the wall, where she stands, and where she turns to face the faucet. Mark the planned placement with light strips of painter's tape. Look at the layout from the doorway the way she will see it coming in. If the marks look random, change them before you press anything down.
Press each strip in order
Peel one strip at a time from its backing. Start at the middle of its planned spot, lay it down, and press outward toward each end with your palm. Run a folded towel across the strip to push trapped air out. Keep the strips the same distance apart so the floor reads as one pattern from the doorway. Do not stretch a strip to fit a bad mark. Peel it and start again on a dry surface.
Test it the way she will use it
Wait the time the package gives before anyone stands on the strips. Then have someone with you step in, stand, turn, and step out slowly, the way she will. Press each edge with a finger and check that nothing lifts. The first test is with a helper in the room, not alone. If a strip lifts, note where it is, and do not walk on it until it is fixed or removed.
Write this down
Write the product name and the surface it was made for. Sketch the floor with each strip marked. Write which person checked the edges after the install, and what you will look for each week: edges lifting, grime in the gaps, strips that have gone dull or slick. Keep the package directions with the warranty, if there is one, and note the replacement guidance from the maker so the next person knows when the strips are done.