If this were a young man say... in his early twenties, then I could see where you might be able to put your 2 cents in.
I love my brother, who is 44, but, I am past trying to teach him anything that he doesn't ask me to teach him.
People will ask when they want to know. Your brother isn't asking. Let him figure it out on his own. He is an adult. You both have your own choices to make. You can't control people. You can only control yourself.
My brother isn't voting for the candidate that I am voting for. I have politely stopped talking to him about my political views on the candidate that I am for. He doesn't want to hear it.
I love my brother, just as you love yours. I try to allow him his free will.
Give your brother breathing room. If he wants your advice. He will ask you for it. Then it will be welcomed advice, more easily received by him.