My Buddy Has An Open Wound When Canyoning A Few

My buddy has an open wound when canyoning a few days ago, this became infected with river water.. The hospital in vietnam gave him antibiotics but the wound is still infected. Today we drained out some pus and a thick yellow substance similar in appearance to snot, now there is a hole in his leg.. I think this is the inflammation? My question is were we right to take out this substance/ shall we go to hospital / he says it feels better now etc any help would be much appreciated as whilst I know a fair bit about wounds, this is out of my experience! :)