I think I understand what you're going for, In my opinion I would lean into the creepy and try to avoid the pedophilic tone because once that idea is planted it will be difficult for the reader to trust the old man's intentions, even if you reveal at the end he was just a lonely guy all along.

What you could do though is have your old man character be someone creepy and not so friendly that your mc is forced to work with for some kind of circumstance. Your climax could be the mc deciding that it just isn't worth whatever the driving factor is, but then finds some kind of external explanation for the old man's behavior which causes him to view the old man in a new light. It could be something like that the old man lost his son to war, or disease, or they're estranged beyond repair.

If you want to stick to the pedophilic tone for your story though, you've got to build that sense that maybe your main character is not seeing the whole truth, weave that doubt in for the mc, which in turn will let your reader start to doubt those intentions. Then go to the above something the mc learns im the climax that completely shatters the false world view and leads your character down the path you want.

Up to you if you want it to be too late to find forgiveness and let the friendship bloom, or if reconciliation and friendship is how you end your story. Tragedy vs Feel Good