So crazy! I had one of those calls years ago from a Nigerian (or some country??) person of nobility who just needed me to give him a small loan of $20,000 to help unlock his fortune for which he would repay me 10 fold! He even had an accent. Hahaha! I laughed at him and said you're joking, right? Imagine! He hung up on me!
What's scary about your call is that he called you grandma and used a family name to try to get to you. FB stalker? It's a common scam to prey on elderly people in exactly that way, claiming they desperately need grandma's help and can she wire some money. It works too, sadly. If you still have the number you might be able to report it to whoever takes care of phone fraud (post master general) but if the number is being routed through Mali from the US, they cannot trace the person beyond that.
And no, I'm not calling you elderly.
You obviously aren't, which is why he didn't try too hard with you.