I think it's just a fanservice cover, not necessarily representing anything that'll happen in the actual comic(s), but just something for the fans to enjoy. I should mention that Carnage in the Ultimate Spider-Man cartoon is derived from how the Ultimate comics handled the symbiote, as an experimental hybrid of Peter's DNA with the Venom symbiote, and Cletus Kasady never appeared in either. Probably for the best in the case of the cartoon.
And for what it's worth, I can somewhat relate to what you said earlier. I had a great-aunt who died while I was still in college, and in retrospect, I regret not being there for her as much as I could've been myself.