Father's FAG record in the profile needs the sameas=no, as stated, since the FAG is for the son, not the father. You don't have any dates in the FAG for his parents, just their names, but it looks like you found a source for the son that mentions the parents, so that is a good source to include, also, which helps to prove that the info on the FAG is correct.
I have updated the father's profile with the full Find a Grave citation, including the FAG template, so you can see the formatting. The same source can be copied to his son, but change the sameas to Yes, since it is for that person in the profile.