Well to start off with Apple did their own thing! The SSD’s Apple used are custom to their needs and are not M.2 compliant!
Here’s a good guide to review [https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades|The Ultimate Guide to Apple’s Proprietary SSDs] You’ll see your friends system is using a Generation 3 SSD which uses a PCIe 2.0 2 lanes using AHCI.
So you’ll need this [https://eshop.macsales.com/item/OWC/MAU3ENPRPCI/|OWC Envoy Pro Portable, Bus-Powered USB 3.0 Storage Enclosure] to hold the SSD. In addition you’ll need to connect it to a Mac system to gain access to the files.