Hey, Seren,
I wouldn't know where to start (will give it some thought), but Coach is right. A mother who was trying to minimize or totally excuse an adult son's behavior, has a whole treasure-trove of cliches to come up with.
But a mother who feels her son is "basically losing his mind," should be heeded.

Gardener

"My soul, be satisfied with flowers,
With fruit, with weeds even; but gather them
In the one garden you may call your own."
Cyrano deBergerac