I'm glad your son is at least safe with you and you can monitor him...thats a step in the right direction. I'm sorry that there isn't a mind trick or sure-fire way to convince him to get help...the minute someone thinks of one, they'll be a millionaire.
It's clear that he's having a psychotic episode and needs medical help, but unfortunately unless he says he wants to hurt himself or someone else (or acts on that), it's almost impossible to force treatment upon him. You can call an ambulance to come and get him, and they can do it, and he'll at least get evaluated and medicated once. His lack of hygiene might get him declared unable to perform the functions of daily living, which is one possible criteria for commitment. You never know if you have a window of opportunity or clarity that will work, so you just have to keep trying to create them.
I'm sorry that I don't have better information for you. Keep doing whatever you did
that got him to move back home.
With your husband...try not to argue against each other, but side with him in his frustration with you son's mental illness. Take the stance that both of you are facing this together...that no one wants this to be happening, and if anyone could change it, they would.
My best to you, Anna