[US] Canada Attorney says we have A LOT of money claim due to same last name.

So this random attorney from Canada supposedly found us with the same last name of the dead person that had no luck in finding other family of same last name. Basically there’s a LOT of money (I’d say over 5 million dollars to give an idea of how much) to be given to us but it feels to good to be true and the worst part is my dad believes it but I don’t and told him about this subreddit. We have no idea on how this so called attorney gotten our information which I find suspicious but my grandma was Canadian but no idea if that helps. I highly doubt this is real but I need everyone’s else’s opinions on this so my dad believes your guy’s words! So overall, is this a scam? Anything or any advice given would be HIGHLY appreciated as I want my dad’s head out of clouds of gold as he’s fallen for many scams before.