If they have been raised together they will cry for one another if they cant find them, as far as im aware he should be fine, try and spend some time with him for the next week until it sinks in his friend is gone, he may continue to cry on and off for a very long time. If he has chickens or other poultry in with him this may help him recover. I guess you have to think of it as, if you grew up living with one other person and they suddenly disappeared you would feel lost, would you not? From my experience with turkeys (which has only been a year), they are very clever and social. Despite this as i said before he should be able to live alone but i would recommend buying him a female. I wouldn't recommend other poultry because I have heard if turkeys are not raised with other birds they can kill them.