Now your friend is just plain funny.
If he is doing well with Senkos in a retention pond then let him have his fun.
I bet he knows he would phloch if he went fishing in a real boat and had to use other baits when the Senko bite is turned off.
I would pepper him with questions about what colors he uses, the sizes, presentations, length of his rod, line test, hooks, how he rigs the Senko, has he tasted the salt in them, does he use any weights, where does he buy them, how does he store them, does he use any scent, has he used any coloring, like JJ's Magic, how long does he let the dinks run before he sets the hook, has he had any problems with the dinks swallowing the Senkos, and anything else you can think of to drive him nuts.
He will either continue to brag or run away when he sees you.