Abscesses and founder/laminitis can often go hand in hand for a horse who has a history of founder/laminitis. When was the horse's last episode of laminitis/founder. If it was my personal horse I'd probably be cautious and treat as if the horse is having a laminitis/founder episode and treat the abscesses as they come.
Might be time for a second opinion since you haven't gotten any answers.
X rays were done early on. The vet is from a big clinic. The farrier has a lot of experience with laminitis and this horse's past and is stumped. Horse is walking on his toe...the problem is in his heel, so I think that is why laminitis has been more or less ruled out. I believe the last episode was over the summer.
I am hoping it is an abscess..horse is probably close to 30 and has several other health issues.