He talked me off the ledge and within a day had transitioned my troublesome projects to others and moved me to a four day work week to recover. He had to run this by manager's three levels up, do an insane amount of HR paperwork (fulltime -> not fulltime, pro-rated salary adjustment, etc.). All this happened in a space of two days.
I stayed on a four day week for a couple of months. It was magical. He retained my reduced workload when I came back full time.
His first comment when I initially cracked - "you should have come to me sooner".
The quick reaction, sympathy and support I got cemented my loyalty to an outstanding manager.I'm still here a couple of years later.