Get something like a likit holder or a roller salt block something for the horse to distract itself with. Grooming is always a go too keeping up the bond and time spent together is essential. You could also do something relaxing hand graze or play music have something to pay attention to that's not the fact the horse is on stall rest
Grooming is essential! I would also invest in a salt block/rock, likit or ball to help his mind. If you're interested, look into clicker training, he will love it and it will give you two something to do while he's cooled up!
My horse has been on stall rest for 9 months recovering from extensive trauma to his feet. Official diagnosis last fall was a strain to the deep digital flexor tendon in his right fore, along with navicular bursitis in both front feet. The road to recovery has been slow, but I've managed to remain positive (and keep myself busy) by doing these ten things: http://paperchasesandpetticoats.com/health/survive-stall-rest/
Lots of grooming, love and cuddles. Also a jolly ball or likit is a good idea so he doesn't get bored.
Grooming your horse. Loving on your horse. Giving your horse treats. Feeding your horse. Clipping your horse.
Hand grazing is really good enrichment for him and if you brush him at the same time it's really enjoyable for the both of you.
A jolly ball is nice and if u can I would take him out on some walk and geez also give him a really good brush. This can also give u time to bond together.