Hi, My 18 Year Old Son Has A Drink Problem,

Hi, my 18 year old son has a drink problem, does not live at home and does not eat well or look after himself well. I managed to get him to the GP and got blood test results yesterday which said his Vitamin B level is 176. He has a prescription for Thiamine tablets once a day and vitamin b strong compound tablets 3 times a day. I am not confident that he will take his tablets though? What should I do next please