The only bright spots to this whole thing is that A) A vet DID see Max and was/is presumably treating him, and B) he was alive at the time of the first hearing, or the uncle would have said something about his passing.
I can't believe they would let a beautiful horse like that go downhill from lack of care if they have ANY feelings for horses. The uncle must not know the jailbird nephew very well if he believed that the nephew was married to you, and that he owned this horse and could sell it. Didn't he ever wonder where a jobless, moneyless person like that got such a horse??
I am appalled at the way this has gone. At the very least, at the hearing, I think you should make a very quiet, very polite request for a report on Max's CURRENT condition from the vet who saw him (and we hope is continuing to see him). You have been much more patient than I would have been, but you are handling it the right way, and I commend you for it.
Prayers are with you.