"Heh?! Mamma Mia? Heh?!" Yikes.
I'm probably alone on this one, but doesn't he seem like that spazzy uncle at a family reunion who holds court in the bar telling old off-color jokes and asking the women of the family to sit on his lap?
Notice, though, how he contrasts art, music and -- hooahh! -- WAR! He's the tough war guy, not the effete music guy... even though he loves 'Dancing Queen'. So we have to give him credit for this: he was able to shoehorn his POW experience into a chat about -- heh? -- Abba.
What he's really saying here is, Shut up, I'm not a gay!