Boyfriend called my 5 year old ignorant

I have two kids from a previous relationship where there dad isn't involved, i met my current boyfriend and i really liked him, he treated me good and was good with my kids. We've been together 8 months, i recently found out I'm pregnant. I've noticed things he does that just irk me. Like how he treats my kids. My oldest has minor brain damage from strokes he had when he was younger. He'll pick him up by his feet (playing) but it scares my son. Also the other day he called him ignorant because my 5 year old got upset that my bf deleted his minecraft inventory on accident. To me, that's not okay. He's 5! I'm just not in love anymore mostly because how he treats my kids..and he thinks he's awesome with him. I've talked to him about it before and he's like..oh i thought i was great with them.. he's 24, im 27. Just don't know. Needed to vent i guess!