If he is 1.80m, then similar to uncle neo and ispyyy. Best to
keep his weight between 60 to 65kg maximum. Anything more than that
is considered a little flabby for guys. Also tone and go to
the gym. Watch his diet and jog frequently and don't drink too much
beer. 
FYI, 65kg for someone 1.8m is way under weight. Should be 75kg
(No flap included)
