1.12 y.o 2.Never [3.No](https://3.No) 4.First off a majority of stuttering children will spontaneously 'cure' stuttering themselves and if you son exempts from this, then sorry I'd say he will for sure live a harder life than normal but what you can only do is that you spare no efforts for him to achieve speech therapies and give him spiritual supports against bullying, teasing, being poked fun at and etc. As for now you don't need to worry about him too much and just let him talk what he wants to say, unless don't tell him stuttering is wrong, stuttering is devastating and similar stuffs, which can lead to him being frustrated and upset about stuttering.