I have a colse frined like this, I just told him that he should socailise at school more often, open his mond up to other people different from himself. If he meets a girl/boy he likes then get to know them as much as possible and practice asking her out in front of a mirror untill he feels confidedt enought to ask her/him out in person. It worked he now has an amazing girlfriend. Good luck to you Rubenato :)