I'm a hoof care practitioner with lots of experience rehabbing founder & lami. I do not recommend metal shoes, definitely not heart bars. I don't advise shoes for sick feet and believe they can only be used with minimal negative impact if the feet are healthy & strong.
Very basically, laminitis generally comes about through dietary problems. Therefore, concentrating only on hoof care is not going to be successful in rehabbing. Treatment needs to be holistic. In conjunction with other management changes *correct* hoofcare will generally lead to full rehabilitation.
If your horse already has rotated or dropped coffin bones, then it's not just lami, it's progressed to founder. It's likely his heels are high, keeping the frogs out of a supporting role and his toes are probably long(stretched forward) and flared, as the walls are disconnected with the feet and forced into an unhealthy angle. Keeping/making heels very short(compared to what is fashionable in many circles) and keeping toes short & backed up should help avoid or correct rotation. Keeping the entire walls level or near level with the outer sole will prevent them 'dropping' further. Using hoof boots &/or frog support pads will keep the horse comfortable & allow exercise with *correct movement* where necessary, until his feet become healthy enough.
I appreciate this view may be against your vet's & farrier's advice. Unfortunately it may be because they have little & outdated information about hoof function. Slowly this is changing & more & more vets & farriers are becoming educated on the pros of *physiologically correct* hoof care & management. It's up to you to do the research & make a decision whether you will follow their advice or follow the sort of principles I'm speaking of & find other professionals to help you. To this end, hoofrehab.com & safergrass.org are 2 great sites to begin with.