Adding a lock to a private room door in a memory care center. Has anyone done this?

My mother in-law is in a Memory Care Center in Georgia. She has been diagnosed with dementia but is in pretty good shape. Mobile, knows our names, where she is, etc. She is there because they allowed both her and my father in-law stay in a room together. Unfortunately, he recently passed as he was much further along with his dementia. She basically doesn't mind being there except for the food (it is too fattening for her 90 year old girlish figure) and other residents wandering into her room uninvited. Especially at night when she is sleeping. I was thinking about a finger print lock where she could lock it from the inside with a deadbolt. We could set it so any print will open it from the other side but would be enough of a deterrent for the residents. At this point, we don't know if it is allowed, if we can fight to make it happen, etc. Open to thoughts/ideas.

Thank you for reading!