What are his intentions?

So 2 years ago I was dating a guy for 9 monthd.
Things didn't turn out good and we didn't talk to each other anymore.

I am starting to get along with his younger brother (not in a romantic way but a friendship) but we never talked about me dating his brother but I know for a fact that he knows about my past with his brother because he asked a close friend of mine whether he knew about that or not.

So whenever we talk I notice him talking a lot about his brother and also about things his brother wanted to do with me. Like drinking alcohol etc.

What exactly does that mean? Or am I just overthinking?
My best friends also think it's strange.
What are his intentions?
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