While Flynn has tragically lost all of his impeccable sword skills (rip), he will be trying to talk doubleJohn down and when Pal is particularly threatened, will def make an attempt on him that will almost certainly be rebuffed! When that doesn't work, he'll snap back to his senses and realize where he's most needed: healing!

Flynn's a long-range combat healer, meaning he can cast spells in the middle of a fight and aim them basically anywhere, so if you want someone to get hit and then get right back up again with a little holy light magic, Flynn's your man!! Would love to have him dramatically rescue someone from the edge of death only for them all to bite it at the end of the cycle anyway, oops.

tl;dr plotting opportunities are "yank Flynn away from the fray after he does something dumb" and "get healed idiot"