What I did for my story was made a comedic character who, with his weaknesses, ends up playing a bigger role in the story than once thought in the beginning. I think the trick is to balance, at least for me, the silliness with the serious. After the bigger role is revealed for the funny character, he still has opportunities to interject his goofiness. My story is apocalyptic, and I guess his reasoning for being goofy is to combat the fact that his wife has been stolen by the bad guys. So I guess: give character’s comedic sides purpose, instead of just branding them as the comedic relief just because.