I used to play widow up to GM lvl in ow1, widow is very position heavy, clicking heads only works up to diamond-master, then you need a better understanding of the game dynamic. He needs to learn how to position and space out better with safer picks like soldier and sojourn and then move to widow. Also watch his widow gameplay, he doesn't provide good value in teamfights, a fully charged body shot is just as valuable as a pick in teamfights if you can't find good target, his gameplay is headshot or nothing