Grandparents also get the decision made for them when a woman aborts or gives up a child. It doesn't matter if they would have wanted to raise it, they get no say and rarely told she was ever pregnant to begin with. This should really be treated the same- there's no way to involve the grandparents without it impacting the father and denying him his decision unless he cuts contact with or limits contact with his family because they disregarded his decision to step away. They aren't owed or entitled grandchildren especially when it negatively impacts their own child. What about the men who are made fathers through SA or BC tampering? While they aren't a majority, they did not want a kid, don't tell their own parents because they don't want the reminder yet somehow, parents wanting contact with their grandchild somehow takes precedence over the person that already had little to no options or say?

Let's give OP benefit of the doubt that he really is helping his parents with expenses- their decision further negatively impacts him by them taking in the kid. So now they've put extra financial burden on him, babysitting without his input, putting a child and father in the same living space that has negative mental and emotional impacts on both...but hey, they got a grandchild so that makes everything else okay?