mellow I am so sorry you are going through this. You say your husband has trouble showing emotion but it doesn't mean he isn't doing all he can to set things right, he must feel betrayed and cheated by his family and very responsible for letting his wife and family down, but often men feel they can't show weakness and need to put on a brave face to those around them, I'm sure that's what he is doing.
It doesn't sound like he took the money without any regard, and he probably feels terrible and just wants to keep working to keep the business afloat. I get it, I really do, it's hard on you and you are suffering also. My DH is the same way, he keeps money problems from me (but he'll get angry at times and criticize for e.g. not turning lights off, buying something we needed for the house etc, and it takes me a long time to dig down and get the truth from him, that he's just stressed about our money. It would be so much easier if he would just be more open but I think it comes down to male pride and a feeling that he should be doing better for us.
I think the best thing is to just be there, let him know you love him and support him, that's what he needs right now to keep going, and just have faith that things will work out one way or another in the future, and you can't magically fix this, just be supportive and let him know you are on his side because it sounds like he is struggling too, but has a hard time expressing that.