My dh had this last night - “hi dad, this is my new number” and our ds had told us just that morning that he was going to get a new phone asap, so just completely assumed it was him - our brains are so keen to make stories and patterns that fit that they don’t do us any favours here!
Dh asked him about why not use the old SIM card and got an excuse, and then the request to transfer money came - about 2K in two transactions to some woman’s bank details. At this point Dh was thinking that either ds was getting scammed, or that he’d done something stupid and owed a massive debt somehow, and was asking ds to phone him but obviously he didn’t. He tried phoning the “new” number on WhatsApp, no reply. Asked what the money was for - a MacBook! Phoned ds on the old number and asked “why are you sending a woman money for a MacBook?” Ds very confused! Dh realised that he was the potential scam victim not ds.