All of his limbs look very swollen which is indicative of MBD. That could definitely cause a fracture or weakened and bent bones. Either way, a vet trip is best. They should do a fecal and may give him fluids to help with dehydration and a shot of calcium. They should also give you pure liquid calcium to administer orally to help with his condition.

He is thin, but not so much so that he can't bounce back with the right diet and supplementation. With the MBD I would limit his climbing space somewhat until his calcium reserves are back up to par and his bones are strong enough to be able to handle jumping and climbing again.