Sounds like he’s a secular kinda guy who probably promised his Bubbie he wouldn’t eat chametz during Passover or something. Or here’s another guess: some Jews I know use it as a sort of Lent-like week to cut out the carbs. And in general, secular Jews who do not hold to some of the more stringent entire lifestyle rules like keeping kosher or davening every day will often obey at least some High Holy Day rules in order to maintain their sense of their own Jewishness. Like fasting on Yom Kippur, shaking the lulav and etrog on Sukkot if walking by the volunteer Hasids in NYC, or not eating chametz on Passover.
As to the pork: has nothing to do with Passover; prohibited 100% of the time for people who keep kosher. I bet he tried it because he doesn’t keep kosher but also doesn’t normally eat pork in day to day life, and so took the opportunity to try a bite or two. I was raised in a secular Jewish home and we didn’t keep kosher but also didn’t eat pork, ever. College was like this whole world of meat opening up for me, but all I could do for the longest time was steal a bite off my friends’ plates, till I became used to the flavor and texture. Bacon was easy because I’d had turkey bacon before, but ham took by far the longest to like.