Let your sis contribute. I know she was not well. I hope she is recovering. Let her help. It may actually help her. You absolutely need to have some overnights away. You will become a wreck, otherwise. With caring for an Dad who has Alzheimer's, I suspect you sleep, with one eye half open. I mean, honestly, can you ever totally relax? I think you are under an awful lot of stress. Even your brother-in-law might be open to taking a night shift now and then. Sometimes folks are slowed down from offering help for fear that you will take it as them taking control away from you. Invite help when you can. A few hours in the afternoon . . . Even a nephew or niece can pitch in. Down the line, they will feel proud to have contributed. Use your imagination to involve them.