My 8 year old son has started to stammer

My 8 year old son has started to stammer His dad has a stammer, our son had a stammer at 3-4 years old but it went away and now he’s 8 and he’s started stammering again the last two weeks. Will it go away? Is it a possible phase? Googling it the usual age is 3-5 years old that it starts and stays. What do you think?