My mom wanted me to find out if anyone knew what the rights are of a grandparent?(We live in ontario).

In which area of topic, please be more specific. I don't think I understand your question

I was wondering if there was any legal rights for her??
My brother is having a baby and his girlfriend has already said that if we do not buy things for this child then we will not see it. She is withholding ultrasound pictures as a punishment to my mother for her reaction to this pregnancy(this just shows how childish she is).
She has a child from a another man and she has already stated that if we were unable to provide her daughter with a gift on her birthday, christmas etc... that we were not welcomed to come. We have never mistreated her or her daughter, in fact we welcomed both with open arms and have helped her more than her own family.

We know that she is going to continue on acting like this and using the baby as a pawn so we just wanted to be prepared if we needed to be.