Sir, It's For My Friend..he Is Now 24 Yrs Of

Sir, it's for my friend..he is now 24 yrs of age and weighs just 40kg and,he is so thin too. He used to say that he was very fat at the time of birth so that his parents neither took him outside due to his weight. Apart from that he says that his stools are always very loosened, so that he is having a doubt that whether his body is absorbing the vitamins he actually eating...so sir pls reply at the earliest..