To take him back into the home, even temporarily, it would need to be agreed by both yourself and your husband. From what you write that seems a non-starter.
Your son is 22 and there are times throughout our lives we all feel like crying but one should get the emotional stuff out of the way, accept what sympathy is offered, and then start looking at solutions. I suspect mothers are more emotionally affected by sons' distress.
I think you and he, and very likely Mr Smow too, need to give some thought as to exactly what his problems are, and how to proceed. Listing them may be a start.
The mood swings suggest some psychological help would not go amiss. That might be simply counselling or maybe something else. Perhaps a trip to the GP would help.
Leaving his responsibilities to his daughter and her mother, by fleeing 3 hours away, does not seem something one should encourage. Although if the details of this situation were in earlier posts, I do not recall them.
Naturally one priority would be to get employment. Maybe easier said than done but one has to keep plugging away until one captures a break. Try to be as encouraging as possible.
But stay firm in your decision.
I understand getting others to work out the wood from the trees is not easy. It was only this weekend I was accused by someone of not treating their issues seriously when I had been the very height of empathy and sympathy and encouragement at all times. It's very difficult to get others to see what is true sometimes.
Good luck.