Old Finn didn't know that the afterlife felt this weird.
He can't see nor hear anything, he just feel like he was wrapped in a slimy and warm liquid. He initially thought that he'd be...you know, somewhere...
Like, he'll open his eyes and find out that he arrived in a vast field of greenery where the breeze feels cool and fresh, that there will be others aside from him, enjoying an everlasting peace. Or like, the complete opposite of that.
Maybe even somewhere in between. There's also a miniscule chance that he'll wake up and realize that he was sent back in the past but honestly he never even considered that.
So, he wasn't really expecting this. This afterlife feels really weird. It's as if he's being digested by something, which is horrible. And the fact that he's semi-conscious while that's happening makes this even worse.