Ex doesn’t like our son with downs

My ex girlfriend and I have a three year old son with downs. It was so hard on her that we split up, and I took him. I try so hard to keep her involved with him. So I request she goes to our therapy appointments. When she comes she scoffs, rolls her eyes, and is rude to the point the therapist has asked she no longer come.At home, I’ve seen her put stuff just out of his reach and take a certain delight that he can’t move well enough to get it, or knock things out of his hands. She doesn’t know this, but once I saw him try to hand her something and she knocked it on the ground.He loves her, he waits for her to come over, his whole being changes around her, he doesn’t look at other people like he looks at her. He was sick recently, and only wanted her. To her credit, she was good with him.I don’t know what to do. I don’t like her around him very much, but it seems like he’s motivated by being near her. She let him sit on her lap and read to him yesterday and I thought he was going to melt he he was so happy.Does anyone have advice on how to help facilitate this relationship? via /r/Parenting https://ift.tt/2q9PXQg