Kleiman involvement in Bitcoin's creation is no more credible than Wright: Kleiman was an IT guy who demonstrated no particular programming experience (the only evidence of him programming anything other than a trivial windows registry editing automation tool, written in visual basic). While it's not physically impossible, there is no particular reason to suspect him over (say) the guy behind the genius bar at your local apple store.  The only reason anyone ever talks about Kleiman re Bitcoin is because of wrights "leaked" (and now shown to be forged) documents wrapping him into wrights 'tulip trust'.

Kleiman's death is relevant... but it's relevant because by being dead he's the perfect unwitting accomplice.

When you buy into theories about Kleiman you're buying into Wright's fallback story.  Some people are never going to believe the brash and technically clueless wright was behind Bitcoin,  but they'll more easily believe the inaccessible deceased guy did the hard work and for wright's scamming purposes that is generally good enough.