My loved one is 90 years old, 5 feet tall, and 140 lbs. She is quite heavy and when she falls down (usually on her butt because her legs are no longer quite as strong to carry her weight) sometimes she falls in cramped locations (e.g. hallway, on the bathroom floor, etc.). I've watched videos on how to help an older adult get back up on their feet. They put them to the side, then on their hands and knees, then onto a chair. This is impossible when you're in a cramped location like a hallway because you can't physically move them with all the space that these tutorials assume. How do you get someone who has fallen, back on their feet in a cramped location?
There's a secondary reason for doing this: you don't need to injure yourself trying to lift her in a bad position, where you can't do it properly. If you are the caregiver and you become injured - and thus, can't provide care - your loved one won't be able to stay in the home.
How does your mom get about? Does she use a walker or a cane ? My aunt is almost the same size and age as your mom. She is probably not 5' but tells people she is 5'2". She weighs about 144 - 147. She uses a cane but gets around very well. She is also 90. What's even more amazing is she fell this morning! The first time in several years (that I know about ). She got in a hurry to get to her door (probably without her cane ) to let her aid in. When the aid got to her she was on the floor in the hall. The aid called me to let me know. Said she got her up and she was fine. I didn't ask how. My aunt has always been able to get up from the floor but she usually crawls to her chair and pull herself up. I think she is able to do this because she gets physical therapy fairly often. This helps her keep her balance. So you might consider asking her dr to order it for your mom. Her neurologist wanted her to have it. She has mild dementia so it's a boost to her cognitively as well.