I am so sorry that you have to go through this.
The truth is that you do have to go through it. Who knows why exactly his mother is there with him, perhaps he asked her because he wouldn't be strong enough to face you, perhaps she's just a busybody. Either way, he/his mother has came to some decisions regarding his recovery. Now, you are left dealing with it.
Everyone thus far has given you some great advice.
I know it hurts real bad, but I promise, it gets better. Focus on yourself for a bit and on your children. I think you will find that they are just as scared and confused as you are. Like firebolt said, Pinterest has some awesome kidlet ideas and adult craft stuff too!
For about the first month without my husband,I just kept on saying, I just have to do the next right thing (a mantra i read at SR that gets brought up often). And eventually the next right thing was easier and I didn't have to have such tunnel vision. Is it a struggle some days? Yes. But is it worth it, for my well being and that of my children? Yes.
Sending you happy thoughts