As I noted on FB it's hard to recommend a place without knowing where these people are.

I hope the son can find Feliway or another calming med, if for no other reason than to make the cat feel better AND to have a NEW vet see if the DC surgery might have left some painful stuff behind that could be fixed. Can't change the declawing but perhaps can mitigate some of the effects.

Prayers for the son and the cat. I hope the wife calms down and cheers up.