Severe hairfall. Should apply shampoo?

At this age i m suffering from hair fall.today i got my head shaved because some said it will help .When i was getting shaved my barber said that there is lot of dandruff. Is it because of dandruff or my father cause he is also bald is it inherited from your parents aur is it stress. I stay stressed all the time. Please suggest what should i do naturally to prevent all this. Please suggest what should i apply to my hair how toh maintain it. And my hair is very thin also.my hairline has also gone very back. How much times a person should apply shampoo? And for how many times should he apply oil.some say that oil is good some say it ain't good. Please help me doctor i don't want to be a joke for everybody for the remaining of my life. Please also suggest the brand for every product.