SIL has been VERY insensitive

I know this is about MIL and I have one from hell. But I need to rant about my SIL at the moment. On the day my son was born and we announced it to family, her and my brother announced they were having a baby. Literally I sent the announcement post in my family group chat that my son had been born and the first message after was her announcing she was pregnant with a scan picture? I found it really uncomfortable and upsetting. I didn’t see why they couldn’t wait to announce on another day. I spoke to my brother about it and he just said they just wanted everyone to know. My mum was very upset with them and spoke to them both and told me my SIL couldn’t understand what she had done wrong and felt like I wasn’t happy for them. Off course I was happy for them but there’s 7 days in a week you couldn’t announce on another day it just had to be the day we made our announcement (yes she saw the message before she sent hers so she knew). We then had a family gathering for everyone to meet our son and a naming ceremony. They turned up and my SIL gave my mum a gift and asked her to open it in front of everyone. My mum opened it and it was a pink teddy bear saying it’s a girl, my mum was quite confused at first until my SIL literally screamed ‘congrats you’re having a grandaughter’. My mum just looked at me and I had to leave the room. I put on a front and was happy for them but I couldn’t believe she did that at my son’s naming ceremony. Maybe it was the hormones but I was so upset and just avoided them. Now every time we see them she makes comments to my mum like ‘oh isn’t it so nice you’re gonna have a granddaughter to go shopping with and get your nails done with, you couldn’t do that with a boy’ ‘Aren’t you so glad you’re not having another grandson’ I just find the comments upsetting and a dig at me? Now the final straw, when we were pregnant we told our family what our girls name would be as we only had one choice and was set on this name. And at the naming ceremony she asked me what we would have used for a girl and naively I told her. She announced the name and it’s the name we were going to use. Yes I know they’re having a girl first but this would have been a name we would use if we ever had a girl and it was a family name on my husbands side that meant a lot to him. I called her out on this and she said claimed she never heard us say this name and she found it online and it was the only name she liked. It’s not a common name at all and I really doubt she easily found this name online. We just left. I’ve tried to speak to my brother but he just says I’m not happy for them and I’m jealous. I feel sad as I want my son to know his auntie and uncle and be close to his cousin but I just feel so hurt by all this. And they can’t even see what they’ve done wrong.