Need advice!!!

So my son is turning 2 in August and my husband and I had discussed that we weren’t going to do a big party yet because I don’t feel comfortable with the whole COVID thing. It was planed to only be my parents and his with 3 of my sons cousins. Now he tells me he is going to tell his mom to do something for our son in his parents house so his family can go over. Like wtf!!! And this is all because his mom wants a big party. I don’t know how to address this…please help!!!