Family/Financial Issues Vent

There has been a situation that I am really trying to not get worked up about, but I am having a very hard time so I am going to vent about it here. I know that this stress is not good for the pregnancy so I really need some help in not letting it get to me. 

A little background: My DH and I have been together since college when we were broke and our parents didn't give us very much money to live on. Then I started grad school so we were living on one income. Long story short, we have never been the most financially stable, and only recently have had enough money to pursue fertility treatments and to start saving for a baby. Once the triplets are born I will not be returning to work for many reasons (impossible to afford childcare for 3 babies, I want to raise my children, childcare would be a logistical nightmare, etc), so we will once again be living on one income.

The Situation: My DH's parents are divorced. It was his parents' agreement that they would each pay for half of his college education. Right before Christmas, his father told his mother (via email) that he was "done" with his half and that it was her turn to pick up the student loans for her half. Instead of them working things out on their own, DH's mom came to DH and said she couldn't afford to take them over and asked if he would handle it. For some reason, it is IMPOSSIBLE for my DH to confront his mother about anything. He talked to his dad about it and his dad said he would take care of it.

Fast forward, almost 6 months, and last week I got a call from a collections agency. Apparently no one has "taken care of" or paid the student loans since before Christmas and the account has been turned over to a collections agency in my husband's name. We have to pay an additional $2k to remove the delinquency and then back to payments for the remaining $5k of the student loan. 

I am freaking out because we CANNOT afford to take on this added expense right now. We are already concerned with being able to afford care for 3 babies on one income. Adding another monthly payment is next to impossible. We are already have some debt we are trying to pay off and a very little amount of money in savings. 

I am PISSED at my MIL because she constantly plays the victim, she is passive aggressive, and avoids any potential conflict. She should have just worked things out with my FIL instead of going to my DH with it. I feel HELPLESS because there is nothing I can do in this situation to take care of it, and it is not my place to ask his parents to try to resolve this. DH just wants us to figure this out on our own. How in the world are we going to afford 3 babies!?!?! How will we make ends meet? Just when I feel like we are getting ahead financially we are taken back by this and I feel like it was not our fault. I am so scared of what this financial stress is going to do to us once the babies are hear, and for what it is already doing. 

I am not sure how you can help. I am hoping for any advice or support. I am allowing this to make me anxious and upset, and I know that is the last thing I need to be right now. If you made it this far...THANK YOU!