In-person, face-to-face trading of bitcoin with cash is done all over the world.

There are simple precautions to take that will essentially minimize any risk of physical security and loss of funds.

This person found a counterparty via "social media". Ok, ... but that's a high risk transaction. You don't have any trust history about the "seller". At a minimum the buyer should have insisted on an escrow of the seller's bitcoin, like all P2P bitcoin trading platforms offer. Scammers and fraudsters love Telegram, Whatsapp, Facebook, Craigslist etc. because it is easy to find a gullible mark who will do something like bring a bunch of cash to meet a stranger in a high school parking lot and actually then get into the scammer's car!!

Here's are some resources for P2P trading:

Tips for local transactions https://bitcointalk.org/index.php?topic=137272

Conduct your in-person transactions safely at your local police station http://www.safetradestations.com

Guide and General Rules for P2P Cash Trading https://www.binance.com/en/support/faq/0bec3bb9292241e99c20136a4d3dbfe6 <-- Tips applicable to in-person cash trading with any P2P platform

But there are bad people out there regardless. Here's a list of attacks, though few of which are related to P2P trading:

Known Physical Bitcoin Attacks https://github.com/jlopp/physical-bitcoin-attacks/blob/master/README.md