Hi, it is good that you care about your friend. It looks like your friend could be stressed about something that is causing him to feel angry. To get the required help your friend can consult a psychiatrist. A psychiatrist will determine if your friend has depression, or bipolar based on his emotional and physical health symptoms. Your friend can also opt for Counseling.
It will be good if your friend can consult a psychiatrist first and then a psychologist.
Next Steps
Consult a psychiatrist and psychologist.