Wow, I'm so sorry you're dealing with this. Always follow your vet's recommendation for any illness or injuries. I'd advise against massage therapy or liniment rubs on the injured area for a while as massage/rubs may actually increase the lameness on a recent injury. That said, your horse will begin to redistribute his weight to his other limbs to relieve the pain in the injured limb, so he could begin to show swelling in his other legs as they take on the weight bearing duties. Massage/rubs on the 3 other limbs is ok and will help him better deal with the situation. You might even consider asking one of your hunter/jumper friends or your vet to show you how to do a leg support wrap while your horse recovers.
All is not lost, though you may think the healing process goes on forever. Use the time to do some grooming and gentle stretches [carrots between the horse's knees to stretch out his back; carrots back at his rib cage to get him to flex]. Try to find some tips on training a horse to stand at halter and practise getting him to stand still or move his feet at your command. Even learning to braid can be a bonding session with him. Simple trick training can keep the two of you active - tricks like head nodding, laughing on cue, or other limited motion tricks. I use to hide treats under buckets or teach the horse to pick up a handkerchief. Not much physical action but a lot of brain activity!
My old boy isn't as quick as he once was and we ran a separate turn out area for him to keep him away from more aggressive horse. Whenever we change turnouts, we put the old boy in the barn until the other horses are done running around, then take the senior citizen out to the area with a lead rope. I generally hang around for a while to ensure there's no dominance stuff. When it's time to come in, the old horse is caught first and keep clear of the crew.