help please!!!

So my husbands two daughters are down for the next 5 weeks. They are 10 and 16. The 10 year old is absolutely exhausting. She talks nonstop and constantly goes a million miles an hour. My husband says she has ADD and that's why she is that way, but I just don't have the energy or the patience to keep up with her. I have a 3 month old and an almost 2 year old that I have to take care of as well. And it doesn't help that when she plays with her 2 year old brother they always end up fighting because she  tries to take his toys. We live in an apartment so going out and playing in the yard is not an option. It's also way too hot to take the baby out and the though of trying to take 4 kids anywhere in public just stresses me out because she's so wild. Her sister is no help because she's always on her phone and doesn't want to be bothered. This is only my second visit with them so I don't even know the best way to take care of them. Does anyone have any ideas on how to make these next 5 weeks bearable? My husband basically tells me to just suck it up and I'll figure it out but I really need some help to keep me from pulling my hair out