Literally nothing.
Give him a high five and tell him to keep doing what he is doing. Since we invent the time machine, I wouldn’t want to fuck that up. Really I wouldn’t even visit.
I would however be expecting a visit from my future self, to get the details on how to solve global warming and a bunch of other issues.
Moldering: “to crumble into dust, to rot”
All the definitions of molding I can find, are about shaping something.