Working a connection with a PM at an asset manager

Im a senior in hs and looking for an internship if i can get one this summer. I have an older brother who's friends with someone who's dads a PM at an AM firm (100m-500m aum). I've never met the guy but he sent his kid to the same hs im at and one of his kids is friends with my older brother. How would you approach this from a networking standpoint if i wanted to get an internship this summer?
I've been researching what kind of asset classes and derivatives (their assets are majority fixed income) they are invested in and I was thinking I could set up an informational interview (maybe over the phone due to the pandemic), try to ask him informed questions to show that im knowledgeable and then maybe he'll give me an internship. What do you think is the best way to go about this as far as reaching out to him, leveraging my connection and what kind of stuff I could talk abt/ask him in the interview?
obviously I am aware that this is late in the school year to be looking for a real internship, and that I would probably be doing a lot of brainless work even in the best case scenario. Im not sure what exact field I want to get into but I figured what you do the summer before freshman year doesn't pigeon hole you at all to a certain industry.