Have Relationship Questions? Ask a Counselor for Answers ASAP
From what you are describing there is a lot of guess work on your part as to why he does something or how he feels. It would be best to ask him directly or to at least share your concern with him. Try to find out if he is having some kind of emotional issues such as depression or anxiety or if he is stressed out by his studies.
In any relationship where two people are involved honesty is the key and the ability to communicate with each other.