Thanks for writing to health care magic.
Tail bone pain
could be because of several causes.
But one thing I could get from your message is that he is sitting in front of the computer for a long time. One should not do that. He should go around and play and lead a active life. He should not sit in front of the Television or computer for more than one hour in a day.
So if he cuts down on his weight and stops sitting for long hours in front of those gadgets on a hard seat his problems will be solved.
Hope this helps