Frustrating Dad.

Ever since I’ve had my son (he’s three and 1/2 months) my father is always saying the things I need or don’t need to do. Saying you don’t need to feed him he’s not hungry, when he obviously is. Telling me you have to do this or that with him when I don’t. He’s now been saying how he doesn’t want milk anymore , how he wants to eat real food just because he’s showing interest and trying to grab stuff. Of course he’s interested in things, he’s growing. My dad has even tried letting him taste stuff which I automatically tell him to stop. To which he replies saying it won’t kill him. He’s already talking about letting him have food for thanksgiving and I said no he won’t even be old enough to eat solids etc. it’s a long list and even my mom says he’s being too much sometimes. Oh and now he’s been constantly saying how he looks like him and he has his eyes and his feet and his this and that, which just weirds me out. He looks more like my boyfriend than anyone. Am I overreacting?