Father-in-law constant negativity. What to do?

Hey everyone, just joined. First some background. Me and my fiancé (both 20) have been together for 3 years and have a beautiful 2 year old stroke survivor daughter. At the moment we live with her dad. I recently lost my job over attendance for having to take my daughter to the hospital and shortly thereafter wrecked my car.

To start, I get it; father in laws typically don't like son in laws. But it's getting a little out of hand. At one point we had lived in our own place but lost everything when my daughter had the stroke forcing us to move in with him. He's 50ish years old, divorced and doesn't work, lays in his recliner or in his room and either complains or literally sobs throughout the day and gets as much government assistance as possible. He's prescribed to pain killers but often lies to doctors to get more than he needs. To make things worse he won't get help even though we've tried making him many times. His 83 year old mother gets his mail, groceries, medicine and often financially assists him although she's in way worse shape than he is. Now, I've sat back and watched quietly and have seen him climb ladders, climb over baby gates, drive, anything a normal person can do just fine; BUT when he notices people are watching he pretends any small task kills him. Even when we were in our own place we had to come over or leave work 3-4 times a week because he would call because he fell, or felt depressed. If we weren't here, we went to the hospital because he'd make a huge deal like he was dying; when really he was just trying to get more medicine. So it was almost pointless to me to live in our own place anyway since he needed so much help (which at the time I believed). If his mom isn't tending to him he makes my fiancé do it. For instance he once woke up at 3am, walked to the kitchen, back to his room, then came and woke my fiancé up because he needed a blanket and a Sprite; both of which were on his way to and from the kitchen.

On top of this, he constantly downs my fiancé and I about everything. The fact I don't have a job, I don't have a car (although my fiancé does, which I bought her so we share) and criticizes our parenting. He's started verbal conflicts with both of us and at one point told my fiancé she just needed to leave me and draw child support. Me and my fiancé are very happy together, we love each other and we love being parents and I'm doing my best to get back to work while working around her work schedule and my daughters daycare. But all he seems to do is try to get her to leave me which kind of hurts because it was mostly my idea to help take care of him.

As I said, I love my fiancé and I love being a dad; but I don't know what to do or where to turn. Living with my parents is not an option because their house is not suited for a 2 year old and my 2 younger brothers (14 and 15) live there. I don't want to leave my fiancé at all but it's starting to seem like he only way out.

A little off topic but possibly the root of his dislike. Our families are polar opposite; my family is well but not rich, about as conservative as it gets, independent and we have a very strong relationship. Her family is very wealthy but distant from each other. Her dad lives entirely off government assistance and his attitude has caused my sister in law and her husband to stop coming around and my brother in law and his family to completely stop contacting him. Again I just don't know what else to do. Help?