When a young person is depressive or suicidal, it is because:
1) His main support system (his immediate family) has collapsed. The psychotherapist's job is to help him come to realistic and acceptable terms with his family members, NOT enter the scene as a SUBSTITUTE for any or all family members.
From my observation, a supportive girlfriend is not a solution because she functions as an extended family member and sometimes becomes additional baggage. (Unless she is a psychologist and is capable of constructing a program for her boyfriend.)
2) His religion does not work for him. Especially if his parents are outwardly "religious" but actually hypocritical.