I appreciate any advice or suggestions to deal with this

Background: My husband has 2 bothers, he’s younger of the 3. one is in jail and the one I’ll be talking about is still living with their dad. My husband made poor decisions in the past but he turned his life around. Like 360, our families are so proud. My husband only talks to his dad and stepmom but not their biological mom, I get along more with their stepmom. Since I’ve been with my husband I see how BIL will bring up the past or criticize him for not talking to their mom, overall tries to put my husband down. It seems like jealously. Anyways, BIL and my husband had the same friends, last couple of years alot of their friends are settling down and having kids so no more parties with drinking games and last minute trips. Regardless of sharing the same daily activities, my husband and I want nothing to do with them and feel they bring toxicity. BIL is beyond single, 40s, no job, video games all day if he’s not helping their dad’s business, and straight up LOVES drama. So we think he’s having a hard time with things changing with their friends. He tends to get worked up over people’s life choices but he’s very obsessed with one friend couple, every waking hour he’s talking about them (positively). Lately he’s been obsessed with the idea of their kid and our kid playing together at FIL and stepmoms house. We try to come up with excuses and he keeps pushing it, we don’t tell him the truth because he will take it, twist it, and make a story out of it. My BIL tends to lie and make up things, a lot of the times it doesn’t add up. He has even made up that I tried hooking up with him behind my husband’s back. As you can see, he makes me uncomfortable, we have to watch what I say, no one wants to confront him about things because he will throw a tantrum. Literally.

So tomorrow is our son’s birthday, he’s been pushing all week to invite this couple and their kid and we said no we just want family and we are making expensive steaks we don’t have the money for them as well. Today, he bugs me over text asking if I have an issue with the girl and that she’s upset that I have her blocked. Ignored it. Plus I’m not sure if it’s true. Then BIL texts my husband the same thing and asking why are we inviting their stepmom’s daughter and her family but not their friends when their friends have been around longer. I see her as SIL and her kids get along with our kid, she’s done so much for us even when there was a tiny disagreement in the past. I knew her longer than the friends so IM BEYOND CONFUSED WHAT HIS ISSUE IS. Right now he’s upset because we said no without explaining anymore, he goes on the PlayStation with their game buddies and told them to block my husband, then started arguments with them for not taking his side and they’re coming back to my husband like dude what’s up with your brother. Why is he pushing this? I don’t even know how tomorrow will play out because of this.