Hoping to get medical marijuana for stress relief

Hello!!
My friend is a 39-year-old father of two, music producer and he has been working in many areas of the entertainment industry for the last 20 years. He has been experiencing anxiety and stresses his entire life which was ignored by others. His co-worker noticed some changes in him during last year. Lately, he has been feeling sad and hopeless, losing interest in activities which he once enjoyed. He is also having problems with memory, concentration, and decision making. His co-worker took me to the nearby clinic and the doctor over there diagnosed bipolar disorder in him. He suggested taking medication. But he’s not interested in taking medication anymore. When I told this to my friend he suggested a clinic in Alberta for medical marijuana treatment which is a solution for his problem. I have heard about the different options for intaking medical marijuana. I guess he prefer vaping medical cannabis. Will this be harmful for his lungs if taken a small hit? What is your opinion? Tell me your genuine opinions!