Hi welcome to HCM .
Any movement in a coma
patient , is definitely a positive sign of recovery. You need to have a lot and lot of patience as the recovery period varies between individuals and depends on the age and cause of coma too.
Since you haven't mentioned the medical details behind coma, in general,
- talk to him everyday about what's happening around,
- remind him some good old memories(through photos/videos)
-frequently use the familiar names and places and
- try giving him verbal commands like , 'open your eyes, try giving him objects to hold' etc.......
Along with the medications he is taking, all he needs is huge moral support ,physiotherapy
and a stimulus to recollect what's going on.
It might take some time(a couple of months) , but don't loose hope.
Although I am a doctor, I am writing this with my own personal experience.
So, be an optimist and hope for the best. Please mention his medical data /reports for a better suggestion on his vital status.
Take care :).