Hello!

First I would like to applaud you on your efforts. You seem like a good man who is genuinely concerned about his wife.
I think maybe talking to her friends to see how they percieve her now during this time could help. I think any measure which can be taken should be taken. Especially if you feel she could harm you or the children. Let her know when or if you do talk to someone about this that you are doing this out of genuine love and concern for her.
I am also worried about how the kids are viewing her since this may be difficult to explain.
Keep a clear calm tone when talking and if she decides not to listen,
you could go to a family member of hers whom you trust or are close with and tell them what has been going on.
I believe that your wife may be facing problems she feels she can't talk about or it may be hard for her to express.
Suggest going with her to talk to someone- at last measures with no hope you may have no other choice but to talk to her mother- Don't be scared.

You are very brave and noble for sharing your concerns. I wish you all the best and I hope I have helped!