My mom's husband won't stop talking about her weight and I don't want to visit them anymore

TL;DR My mom's husband keeps bringing up her weight every time she opens her mouth. I'm getting tired of him and I'm debating if I should stop going to my mom's if he is there, and tell her the reason.
My (30s F) mom (60s F) married her husband Jay (60s M) about five years ago. On their very first date he made a point to tell her "You're the biggest woman I've ever dated" and made a "joke" that she could "order any salad you like". No one in my family has ever particularly liked Jay.
My mom has always struggled with her weight, as has her mom and sisters. She grew up with her mom hating herself all her life for being fat. Then while I was growing up it seemed to always be a subject of conversation and they would always talk about new ways they are trying to lose weight. Her weight has always fluctuated but my mom isn't really that big. She is active and relatively healthy without high blood pressure or diabetes or anything like that. She is overweight but not obese.
Jay is also overweight. I know in a relationship it's important to be attracted to your partner but the way he is going about it is completely out of line in my opinion. He tells her what she can and can't eat, berates her for things she does eat and buys at the store, and gives unsolicited advise on how she can lose weight. Understandably, this has caused my mom to talk about her weight constantly to us, saying she's fat and needs to stop eating, sew her mouth shut, etc. Meanwhile he does not do anything to actually help like go on walks with her, try to work out or cook with her, anything like that. To be clear, my mom still tries. She wears make-up, does her hair, goes on walks and works out. She dresses nice. My point is she's the same woman he married except just a little older.
I have told them how this has impacted me. I have Hashimoto's disease and have struggled with weight loss since my early 20s. I have body dysmorphia and have struggled a lot with my self worth and value as a person because of my appearance and weight. Last year I managed to lose 10 pounds, 20 pounds total since 2020. I've kept it off for eight months now. I've tried to tell my mom how detrimental it is to be mean and punish yourself for what you eat and how she should re-evaluate her relationship with food and see a therapist because I believe she has binge eating disorder. It goes in one ear and out the other, she just smiles, shakes her head and dismisses me. She says "I just need to stop eating so much. I need to stop shoveling food into my fat mouth".
Recently when I was visiting, Jay told her that a healthy weight for her would be 140lbs. I'm looking at him sideways because that's three pounds more than what I weigh and I'm two inches shorter than her. On a BMI chart I would be at the high end of "normal" very close to overweight. But I consider myself to be in very good shape. I have more bodyfat than I would like but I am working on it and I have built up a lot of muscle. That was the day I came over and requested pizza but instead, even though she asked me what I wanted, she cooked some chicken nuggets which everyone knows is way healthier /s.
Jay berated her for buying a huge bag of almonds from Costco (you know what I'm talking about) because they are high in calories and fat. He has given me unsolicited advise, especially when I was heavier. Like, weigh yourself every day, count your calories, opt for low fat, sugar free, etc. etc. type stuff. He brings up my husband's weight a lot and tells me ways my husband should lose weight and asks me about my husband's diet and if he's lost weight. This grinds my gears a lot as none of us deserve to be treated like our weight determines our value and worth as human beings. It's like his entire personality is the guy who gives great advise to people on how to lose weight and his life depends on keeping an audience.
Yesterday my mom told me she went to YouTube on the TV and saw the search history where Jay typed in "How to get your wife to lose weight". She said "lol" but I don't think she thought it was funny. She never addresses how his words impact her because "It will embarrass him" or "hurt his feelings". I consider myself to be an understanding person but I'm at the point where I don't really care about his feelings. He's hurting other people's feelings and not being held accountable. He's making my mom feel like she's not worthy of love because of her weight. She even had a weight loss procedure done (Obera) which worked but she immediately gained weight back after having it removed. She never even told her husband she had this done.
This has kind of turned into a rant session. I feel that his negativity is damaging not only to my mom but me as well. I've worked extremely hard to change my relationship with food and it's working really well. But every time I go over there I find myself feeling gross like he is judging me or going to say something about my husband's size. My therapist suggested telling my mom I'm not going to go to her house if Jay is there (he is there most of the time) but, like my mom, I worry about hurting my mom's feelings. I also don't like being mean to people but maybe it would be beneficial to tell Jay exactly the reason I won't be going over there. I don't see him every looking inward though.


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