TW: miscarriage, mental health

my boyfriend (26M) is very proud of the fact that he was raised “old school”, when I was first getting to know him I thought that he was referring to things like playing outside rather than playing on screens, or old-fashioned gentlemanly behaviour like holding doors open. however the more I’m getting to know him and his family, the more it’s feeling like being “old school” is just an excuse to be an asshole and not have to modernise or improve themselves at all? I (26F) am bisexual, my boyfriend had some concerns about this before we officially got together but told me that it was just his insecurities from being cheated on in a previous relationship and that he’d worked through them and was accepting. multiple conversations with his mother have revealed that she’s transphobic and thinks that any non-binary gender identities and pronouns are just a result of a snowflake generation and people just want attention, obviously these types of comments make me wildly uncomfortable. my boyfriend told his mum that we were attending our local Pride event this weekend (I was avoiding mentioning it but he says he’s proud of me and who I am and wanted her to know), she asked why we were going and he said because X is bisexual, she responded “yeah so? does she need a medal or what?” I recently got pregnant and unfortunately miscarried, I was really struggling with this and my boyfriend suggested we talk to his mother for advice. the way she responded made me feel like I was wrong for being even slightly affected by the miscarriage, she basically said it’s happened to loads of women (I know it has, doesn’t make it easier) so I should just push through and keep smiling and then it’ll just be a thing that happened and I won’t even think about it any more, which wasn’t helpful to say the least. less than a week after she gave us this advice, she went on a tipsy rant about how me and my boyfriend need to stop dwelling on the past (I’m unsure if she was referring to the miscarriage or a previous traumatic pregnancy experience I had some years ago which she’s aware of), we need to forget anything that’s happened before and move on, oh and also she wants grand babies soon so we’d better get a move on - horrendously triggering comments to hear barely two weeks after I had to give birth to our dead baby. my boyfriend again attributed this to being “old school”, because mental health “wasn’t a thing then” so his argument is that his mother was raised to push through and not show emotion or weakness. apologies for the long post, those are the two most recent and obvious examples I can think of, but basically I’m wondering if this “old school” mindset is something that could be a deal breaker? although his mother is mostly the one voicing these opinions, my boyfriend has made similar comments (mental health doesn’t exist, you’re born either male or female, etc) and always defends his mother. I’m so uncomfortable around his mother I go dead quiet because I don’t feel like I can be myself or honest even slightly, I guess my worry is that I’ll wind up feeling the same around my boyfriend and potentially compromising who I am to fit into this relationship any advice welcomed, happy to answer follow up questions as I’m not great at wording these things!