Hearing you loud and clear @Razzle about protecting yourself and your family, which includes your son and future grandchild.
So they are both lot younger than the couple I am dealing with but there are similar issues around the controlling aspects of mother's mother.
I thought about whether my two would ever make it together, and I was very worried that she would never know how to stop and would drag him down. The girl is vegan and controlling and flips into physical self harm at the drop of a hat, so some differences. I have been saved some angst as my son decided to break up with her, as they were not compatible on essential levels, before he knew they were expecting. Now they have decided to co-parent.
That could be a model for your two young parents.
It sounds like your boy will be lovely father and the world needs good men. Stand by him. My intuition says dont push them together if you dont think it will work. Just put 100% support to son and grandchild and be polite and ethical to young mum, and maintain safe distance. Have some faith in court system. At minimum You should get weekend per fortnight which should be manageable and may be nice, and your son gets to finish his study. Later if partying is too bad on other side, and she does not grow up, your son will be in a good position to make stronger steps. Nothing I say is a prediction, just an optimistic way of managing it.
Take Care Nan
there is a little one who needs you.
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