He either ignores me or has an overbearing attitude towards me.
He often pretends I don't even exist or he's really highhanded with me.
to overbear を使った言い方：
ーHe either ignores me or has an overbearing attitude towards me.
「彼は私を無視するか、威圧的な態度をとる」
highhanded「高圧的な・横暴な」を使っても言えます：
ーHe often pretends I don't even exist or he's really highhanded with me.
「彼はよく私を無視するか、すごく高圧的になる」
ご参考まで！
カナダ 
