Coping with Homeless Family Members

This is so depressing. My sister, biological mother, and nephew are all homeless. I've tried to help them avoid being homeless, but their loser decisions have made it impossible to help. My nephew is innocent in all this. He's a good kid, and it beaks my heart that he's homeless.

Here are the loser decisions that led them to homelessness:

1. My sister married an ex-con who is a sex offender. She makes all kinds of excuses for "why" he's a sex offender. For example: the 12 year old girl wasn't a virgin, he was high when it happened, etc. The fact is, he's bad news.
2. My sister has lost more jobs than I can count because she has sticky fingers. I even tried hiring her through odesk to do product research, but the snapshots clearly showed she was on facebook and watching netflix while "on the clock".
3. My biological mother lost the room she was renting through a shelter-diversion program because she let my sister, nephew, and the sex-offender husband stay with her when they were evicted, in violation of her lease.
4. My sister has a dog, and so does my biological mother. I love dogs, but they complicate homelessness.
5. They lie. ALL. THE. TIME. It's impossible to know when they are telling the truth.
6. They emotionally manipulate people.

Right now, my sister says she needs food and a place to sleep while she cleans out a hoarder's house. She says the landlord is willing to waive the deposit and first month's rent in exchange for cleaning the place up. Is this true? I have no way of knowing. A few days ago, they allegedly had a place to stay if I gave the lady $50. The next day, the lady was allegedly in the hospital and they didn't have the keys to access the place. These are just the two most recent lies. Or maybe one is true.

The problem is, I don't know when they are telling the truth and when they are just scheming for money. They know I am vulnerable to emotional blackmail because I lost a sister already. They know I'm scared to death of losing another sister, and they use that to their advantage. They also know that, having been homeless, I have a soft spot in my heart for the homeless.

I really don't know what to do. I'm scared for my nephew, and I'm scared that my sister will be killed or exploited. I can't talk to my partner about these things. He doesn't understand at all. I feel guilty for thinking that, in many ways, my sister and biological mother deserve to be on the street. I feel guilty that I can't just buy them a house to live in. I feel guilty that I haven't called DFS to have my nephew put into foster care. My biological mother is a product of the foster system. I really don't want that for my wonderful nephew. I feel like I'm caught between a rock and a hard place. I can't have him come live with us because I'm worried his stepfather (the sex offender) would make accusations of abuse and blackmail us.

I really don't know what to do. I'm out of money to help them. They are literally sleeping on the street. Their storage unit is past due because they spent the money on hotel rooms. Their stuff will be sold at auction if the bill isn't paid. Last month I paid $250 to catch them up and avoid the auction. This month I can't do anything.

I'll make sure they have food, but I can't save them from their loser decisions. Perhaps being homeless will motivate my sister to ditch the pedophile ex-con loser who's been dragging her down.

How fucking depressing.