Thanks for writing about your cousin's problems. It is a good help you are seeking for him. You have posted this question here under Depression
. But you may keep in mind that his problem may or may not be depression.
A lot of factors are essential to be considered before you can conclude what the problem is. We need to know about any similar problems in the family, any previous problems in himself, etc.
The symptoms you have described could suggest a number of possible conditions. Depression and psychosis
are some of them. Loss of sleep is seen with a number of conditions. Talking irrelevantly and being afraid of everything might be seen in psychotic conditions.
The best step will be to suggest to him (or take him) to consult a Psychiatrist
for a complete evaluation of his symptoms and any necessary investigations. Please do not wait until you get answers from the internet. You may not get a complete answer anyways as there is a limitation of diagnosing via this medium.
Hope this helps. Best Regards.
Abhijeet Deshmukh, MD