Suddenly angry teen boy

I have a new situation as my teen just had his 15th birthday and seems to be instantly becoming angry now. I know this is likely an age thing but in particular I don’t know the best way to handle it now that he has started yelling back at me.

He also is asking me to listen to him more but he is going down the same path 3 times in a row, telling me his view which has not been that rational lately and I don’t know if it’s actually good to tell him it’s not “dropping the subject” or disagreeing appropriately. He’s still not used to those 2 skills and I question myself wondering if it’s that or if he just wants to be heard and understood. If so, what words might help him feel better?

In addition he and his 12 year old brother aren’t getting along too well and he is trying to parent his brother by telling him he is doing something wrong or ordering him around. I’ve been trying to stop this behavior for a few years. How would you handle that?

Thanks so much for your assistance!