I'm done with Kevin Smith, but this sucks to hear about. Never want anything like this to happen to anybody but monsters you actually want dead, like child molesters and such.
My friend had kind of a similar experience, but it turned out not as dire. Showed up to game night really out of it, so we thought something was wrong at home. He wouldn't talk about it, so we played a longer game. Then he said he was having chest pain all day and couldn't catch his breath. We tried to get him to leave to go get checked out, but he said it was just angina. After playing another long game, he texted his wife to say he was staying longer, she texted back to get his ass to the ER. A week and a quadruple-bypass later, he started his recovery.
Whenever someone gives an excuse on why they're missing a game night, I tell them it's invalid. Dude had a heart attack and still made it