I really need help.
I would say this to your husband:
"I'm sorry you two had such a falling out, and I hope you will think a little longer before you decide to put your retirement account somewhere else. If you are honest with yourself, you're doing this out of spite and it's going to damage relationships further. You are a man and you can do whatever you want, I just had to say something because I love you both and I really want you to be able to get along."