The huge difference is that this is the private IP address of his machine (which are basically the same for every device, since it's related to the network you're connected to) and not his public IP address (which shows ISP, country, etc). My private IP address is 192.168.0.20 right now. OP's was 192.168.1.15 when he received the email. Pay attention at the similarity (192.168.x.x).

Also, IP addresses have nothing to do with 2FA.