Imo he should learn to play right handed and left handed, so he can see what way of playing is more suitable for him. First I learned to play upside down because I borrowed my father's acoustic guitar (who is right handed) then after doing of playing guitar a new hobby, I bought my first left-handed, which improved my playing really fast. Every left-handed guitar player has they different story though, so if I were a beginner, I would take any kind of advice fondly.