Interestingly, I was put onto this scam by an acquaintance who had a severe head injury. He has money to invest as a result of a payout due to his injury. But sadly his mind isn’t what it used to be.
I told him it was a scam but I’m not sure he believes me.
After I posted this OP, my acquaintance showed me an email chain in which these scumbags tried to get him to send a substantial sum as an “investment”. He assures me he didn’t send the money but I am not sure whether he did or not. Possibly he did but he’s too embarrassed to tell me.