Father
It's his father, I think the beta father of Doha impregnated his omega father since there is a possibility a male beta can impregnate a male omega, and found out doha's existence after breaking up, and after the omega father of Doha gave birth to him, he left him with his beta father to find a romantic relationship with an alpha (which annoys me so much) so which explains that the man is his father.
Ohhh I see. I was just skimming through the chapters of the raws and I got confused who was choking the mc because the hairstyle and color looked similar to the middle aged dude.
Father or former partner?