one of my good friends played someone and he resighed. the match wasn't that long but i looked at his profile, finding losing most of his games by resighing. its very suspicuis and i don't know what to do

forget about it... nothing you can do.  He is sabotaging his own rating because he likes having an 1100 rating, then going around kicking the crap out of 1700's.

or he wants a low timout ratio

and resigning lowers it

My coach used to say: resign often, resign early!