Personally, I don't see anything wrong with buying bitcoin from somebody you know in real life. You just have to be smart about it. If you can't trust people you know, then how does it make sense to trust random strangers on the internet?
You can't see anything wrong in this until similar thing happen to you, if you know someone too well does that mean you know how they make their money too? Even a carpenter can be a part of armed robber group, until the day they are gunned down you will never know that they are into such thing, are you a kid or something? You should know what I am saying.
In my country, a group of friends at work are all gunned down in a robbery/kidnapping operation that went horribly wrong, later we foud out that they are actors who have acted in several movies before, it was very shocking to all of us.
Some people who are closed to few of them said they are good people that there was never a trace that they are into kidnapping business, this is why it's wrong to trust anyone even if you know them.
The only thing standing between strangers and you online when you want to trade your Bitcoin is the exchange or the dex, they have to hold your digital coins and make the other party to proceed first by sending money to an account before releasing the asset after confirmation.