I think there is something that has been lost in all the discussion. A handicap is supposed to be your "best" 10 rounds out of your last 20. So right off the bat, your handicap is only at best supposed to be a reflection of how you play when your playing well.
So by pure probabilities, if he played 4 rounds during the tournament, then 2 would be his better golf, and 2 his not so better golf. Even conceding that he played 4 rounds of his better golf, they should still at best only match what his handicap his. But for all 4 of his rounds to be better than his best golf, and to be playing in a tournament where there is more pressure, and potential for gag jobs, this just seems very very unlikely.
It could have been the ultimate ham and egg job where his good holes came on his partners bad holes and visa versa, but this is very unlikely as well.
If it smells fishy, looks fishy, tastes fishy.......