Frodo may be Bilbo’s actual adopted nephew, but Merry and Pippin are his younger cousins, and Sam is his old gardener’s son whose family he clearly has a soft spot for and who he taught to read and write, and Gimli is the son of one of his old adventuring friends, and Legolas is, similarly, the son of the Elvenking who named him an elf-friend, and we know Aragorn is canonically his friend as well, who he very possibly could have met as a small child in Rivendell when he passed through, so really, like 7/9 members of the Fellowship are people he can employ weird elderly relative (or the honorary equivalent thereof) energy on if he wants to and I think that’s very powerful.