When you only are responsible for yourself this is a legit thing in my eyes. If this is the life he prefers and he is happy, go ahead.
Doing this when you have a child is an irresponsible asshole move in my opinion. You are forcing your child into a live that just can’t be as healthy for them, physically and mentaly, then a more secure setting (that he had before) would be.
It’s been the same with Christianity for most of the 2000 years it has existed. Christians had so many different interpretations they have been split up into splinter groups as early as 30 years after Jesus death.
Literalism is a pretty new concept, rougthly from the late 19th century.
If anybody is interested about the history, I can recomend Center Place`s newest video, a progressive church that has a lot of historical and very scholary lectures about Christianity and Judaism (no preaching or converting). Their lectures playlist is a treasure. And I say this as a very much not Christian or Jewish person.
Here is their video on Literalism