Can’t stop thinking about this kid

My husband and I took our daughter to a pumpkin patch earlier today and we sat down to eat some dinner. While we were eating there was this family near us eating as well. The “dad” kept putting his son down saying that he looked stupid and dirty and and just kept talking about his looks and putting him down. He also made fun of the way he spoke too...I almost said something, but I didn’t because this guy looked like a freaking crackhead and didn’t want any trouble. The whole time this kid was just sitting at the table looking down and sad too. The mom was just sitting there telling the dad to stop, but he just kept going...what makes someone do this to their child?Then this guy saw that my daughter (who is 16 months) wanted to run around and get up close to their table and kept saying hi, lol. The guy looked at her and was “oh wow, what a happy girl, looks like she has a mind of her own which is good” then looks like his son and rolls his eyes. I didn’t say anything, just gave him the stank eye. I just feel so horrible for that kid and wish that I could’ve done something.