Are nails necessary for dogs? Would it be a bad idea to simply remove them? He probably couldn't dig...and scratching might be a little different of sensation for him...but does he really need these things that are causing him so much trouble?
For cosmetic reasons I wouldn't suggest nail removal...and I really (personally) don't like the idea of declawed cats....but in this case I think I'd consider it. Might take some time to recovery, but then (hopefully) he'd be fine...and not back at the vet yet again for another nail issue.
I don't know if it's even possible...but it's what came to mind. I've got you and Button in my happy healing thoughts