Cali and Ginger have made good points. All you can do is offer not to make the food that he thinks he's allegoric to. Of course, it might be that he eats too much of it and then his digestive system goes haywire.
As for the locked door, it could be something that happened to him as a child at night. Could be someone came into his room and scared him or it could possibly be someone came in and touched him inappropriately. The locked door symbolizes safety to him right now.
All you can do is listen and validate. You can't be his mother and attempt to fix his issues. You need to focus on your sons, especially the one that may need to drop a class. Focus on your sons. Your h is a grown man (little boy blue) and he needs to figure things out for himself.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
