A Friend A Latee 50s Yr Old Male Has Worked

A friend a latee 50s yr old male has worked outdoors doing electrical work and cell communications now for well all his life ,we live in Az , it gets over 110 in the summer. He has had some basal cell carcinoma removed and one melanoma off his cheek, Also a recovered alcoholic he has smoked cigarettes in the past but now and has chewed tobacco for quite a few years 10 and as a young man. (sleeping while having chew in his cheek) also has a opiate dependency which requires medication. I am concerned there's a chance of a deep underlying illness, other than needing the medication .