Do you have those pads? They make pads that attract puppies/dogs to piss or shit on them. I would leave them by the door and see if he goes on them instead of all over your floor.

Try having your sister play with him a lot during the day to tire him out, sort of like a toddler. Don't let him nap too long during the day and maybe he will sleep during the night. There is always the hot water bottle and clock trick that will help him sleep too.