My dad snaps at and is condescending to everyone, including my kids.

I had this whole ordeal with my parents a year ago already. It was them questioning my parenting, how my dad talks to me my whole life (condescending tone, etc), my mom enabling him, etc. It was 2 months of silence. We only started talking because my husband spoke to them and eventually they apologized.

Here we are again. It is about how my dad snaps at my kids and speaks to them in that condescending tone again sometimes. It has made me lose confidence in myself how he has always talked to me and now I see him doing it to my own kids. It has affected me. Now it's affecting my kids. My youngest doesn't even want to make cards for Grandpa or talk to him sometimes... just cards for Grandma. I saw the instance my 5 yr old's heart broke - it was all over his face. The shock. The frown. The slow start to crying. I hugged him. I stood up to my dad. He is in complete denial - I have to FORCE him to say sorry and if he does, he says it like a toddler - insincere and aggressive. My mom was mad when I told her. She said she would talk to him. The next day, I sent her a long message about his behavior- please talk to him. Message included like how it will eventually end up him not talking to his grandkids anymore if that's how he wants to talk to them. My mom showed it to him as I wanted her to and also said he is a great father, grandfather, works hard, etc. I said yes I understand that but that does not allow him to talk down to my kids like he does. Then my dad called and I had the glimpse of hope he was calling to apologize. NOPE. He reiterated how great a person he is, how much he has done for us, etc. When I tried to speak, he interrupted me and as usual tried to talk over me with that low man voice that resonates so I rose my voice and tried to get my point across. He just said I need to stop yelling. I hung up because I was absolutely livid and shaking so much. There's no point in repeating myself.

We're supposed to get together at my in-law's house tomorrow for Christmas eve. I'm going to enjoy myself and ignore him and if he wants to talk to me alone, he will do so with my husband there too because I need someone on my side. He is just going to keep not acknowledging his wrongdoing. Who else has a dad who acts like this??