My girl has been drinking from straws since 12mths. She drinks from regular BPA free water bottle now @15mths. Dip some yogurt onto the tip to encourage him to suck. Try a shorter straw before progressing to the regular bottle sized straws. Hope this helps!
Get Richell training cup, LO can learn how to use a straw too. For my LO, she uses bottles which has prints she likes. She also uses toy kitchen set cups to drink water.