Wow. Kudos to you and your family for being there for these boys. Boys need father figures badly, so see if there is anyone else besides your hubby to step into that role. Maybe a youth pastor or youth sports coach. You named it, FOOD! Have healthy snack options readily available, if you are not a member to Costco or BJ;s or Sam's Club, get a membership now. That way you can save by buying a lot of food! Also make your house a "hub". A place to attract these boys' friends, make your home the hangout. I've talked to a lot of teens who are "bored" on the wekends and end up just hanging out at the mall or at playgrounds or whereever at night! So with snacks, and some movies and games your place will be the one to go to! You might think, but I don't want more kids here!?!?! Well, first you'll know that the boys are at a safe place and you can get to know their friends. You can be the best influence in their lives! God Bless you and yours for doing this.
Oh, boundaries. Definately want to set up rules and clear consequences for those rules that are broken.
Have a chore chart, everyone wants to feel like they belong. Belonging to a family unit is great, so if someone does not do their part they do not get to reap the rewards of the family unit. I agree with the other response in knowing if they have any emotional or bahavioral problems. That could help you out. Good luck and let us know hwo the family's doing.