Yes, Thanksgiving is observed in the US on the fourth Thursday of every November as specified in the 1940s by congress and FDR.

About your ideas: I project myself into my younger self of age 18-30 or so. If I had been asked at those ages to step up I probably would have blown off the challenge out of laziness and a feeling of entitlement, like "it's the old people's job to make this happen."

I would probably have done this for one year, and by the next Thanksgiving I would remember how lonely it was to not have anywhere to go, and I would have probably tried to reboot things.

Unless her younger relatives are downright autistic I bet this happens - they will value the holiday when it is not observed as it has always been.