I think this is something neither you nor the mother can fix. The son may or may not come around on this. It sounds like he has some issues he really needs to work through before he does.

If the mother looks back at her own actions, does she find herself blameless? Were there strings attached to the support she provided? I am not saying your friend is like this, but my own mother has the bad habit of using money and gifts to try to control her children. We all resent her because of this and now know not to accept any 'help' from her.

I do think she needs some help. She needs to let go of her son, at least for now, and let go of feeling that her life is not worth living without him. His demands are not reasonable and complying with them doesn't seem to work.

Her talk that her life is not worth living without him makes me wonder if she has perhaps been too close to him? I'm sorry, you haven't posted anything that indicates your friend is in the wrong, but I think I come at this from the son's point of view because of my own situation.

I hope they can work things out eventually. My brother refused to talk to my mother for some time. My mother made herself available without invading his request for space by sending cards occasionally, to let him know she was still there. He eventually resumed speaking to her.