The man just lost his son. The last thing he needs right now is to wrangle donations from randos around the world and then to figure out how to establish and run a nonprofit.
Josh's obituary specified the Casper Humane Society and autism charities (just not Autism Speaks) as worthy recipients of gifts in his memory. While the sentiment of a memorial bench or a new scholarship or something similar is well meaning, it's unnecessary to establish something new at this time. Worst case, such a thing could attract scammers and other bad actors. Best case, it's an added burden applied to an already grieving family.
If you feel compelled to make a donation in Josh's memory, the nonprofits that Clint already identified are probably the best choice. No need to make things more complicated.