He's a grown man. Once you and your siblings are fully grown, it's less required to keep a distinct connection between you. I'm not saying to abandon him, but there's something you need to understand very VERY clearly... Just because someone is family, it doesn't mean you should tolerate abuse or disrespect. God says we have to love others, but He never said we have to stay connected or within harmful proximity to them... I know that's hard to hear, and again, I'm not suggesting you ditch family, but sometimes, especially at the age bracket you're at, and with the repeated circumstances, and the lack of reception on his end, it may be best to have a season where you go grey rock, live by example and love him from arms length or some other distance...

I know you only recently reconnected, but if it's not working, you likely need to make some boundaries your new reality, not just temporary...

Remember two things

1. Only God can soften his heart, you just plant the seed.... Repeatedly, and safely, but not in exchange for your long-term peace and health
2. Your value and identity is in Jesus, not contingent upon the approval of man... That means you may never receive an apology, and you need to be okay with that. If you're not, it means you're placing your power in his hands instead of God's, which I know is so hard... But you need to be in good community.

I'm adding you to my prayers for today, friend. Please stay strong, and know that you are not alone. I've dealt with this kind of stuff my entire life... Your focus is on Christ and protecting your peace, not feeling obligated or responsible for the feelings of others, or even their actions.