Watch some old Bird videos when he boxes out people, he holds their jersey and shorts near the waist. When he starts to post up try to put your thigh between his legs(at his buttocks area) to get leverage since you are lighter. If he leans on you step back and make him fall on his butt. When you go to block his shot if he is a righty use your left hand it will be closer to his shooting hand, opposite if he is a lefty. On the offensive side if you are in shape and faster than him make him work on defense by running the floor.
As some have already said height wise you're close enough to play with him. I was 5'10" and 115lbs playing against a US Navy bball player who was 6'6" and 225lbs when I was 17 or 18 in Guam and I still managed to block his shot, of course I had hops back then now I will be lucky if I break 24" vertical.
What's the guys name anyways? I used to go to school at Baste for 2 years and trust me there was a time they had crappy players.
ps: Don't forget to use your elbow since it will be sharper than his.
pwede mo rin gawin yung suggestion ni yebo, ginawa ng teammate ko yan dati. without the "akin ka mamaya" haha pero sobrang nakakatawa habang tumatakbo at nagdedefend sya, nakahawak yung isang kamay sa butcheek ng kalaban. sa sobrang inis ng kalaban, nasira laro nya hehehehe
di ko po ksi matandaan ang name nya legarda yata name nya not sure. Boss about submitting the nso nag papagawa lng sila yan eh kahit nga student licence lng ipasa pwede eh. Hindi sila ganoong strict nakakaasar nga eh. Well that's life