This means he survived.
This means we don't know whether he is alive or dead.
May is more probable while might is less probable.... Thats my point of view :D
Originally Posted by RonBee
Luckliy, his friend, who is a doctor, was with him, or he might have died in the accident.
That is a good use of the phrase "might have", but I think I would say the person might have died because of (or: as a result of) the accident.
Can I say? what difference it is going to make if I will use could instead of might
Luckliy, his friend, who is a doctor, was with him, or he could have died in the accident.