How do I keep my husband from getting up on his own and possible falling?

Time for a seatbelt, so sorry you have to do this. Get a rollator and strap him in, buckle at the back. It's either that or a memory care facility where they use restraints. Have his doctor order a visiting nurse if you don't already have one.

Well, it's not easy. In the hospital we often just have someone with them as a sitter all the time that family can't be there, or if they are not right out at the nurses station. Restraint is not permitted, but a Velcro belt as a reminder or a tray on the chair may be OK. They have some alarm systems that will sound when they are first getting up but it depends how critical things are, will it be quick enough (eg is there a fracture that would re fracture with any weight bearing, vs just unsteady if going more than a few feet.) the other theory is to tire them out with lots of supervised or assisted walking so they don't have as much urge to get up all the time. Often this is a very difficult problem!