I'm not a professional, but my childhood experience was very similar to your son's. Started around 4, and at around 4th grade is when it got really bad for me, too. A proper speech pathologist will have an easier time assessing how and why he stutters, as opposed to you and us trying to figure it out. Your son knows, even if he can't articulate himself well enough yet. A pathologist will be able to read him. Luckily I was an extroverted kid so I liked trying to figure out my stutter. Some kids don't want to do that, so a pathologist must for them. That being said, getting a pathologist/therapist seems to be a challenge for you given his father's stance on it. The only strong reason there is for NOT doing it, is money, because it can be expensive. If he gives any other reason besides not being able to afford it, then he isnt prioritizing his son's health. That's a bigger hurdle than I'm capable of giving advice on, so I'll leave that there. Worst case scenario, just try talking to your son about his stutter more often. Try and help him with breathing techniques, going slow, and his vocabulary. Knowing synonyms is helpful for choosing alternative words when he gets stuck. Instead of "bug", he might have an easier time saying "insect", for example. So vocabulary helps. And of course, keep an eye on his teachers and make sure they aren't being cruel to him - it does happen, and he may not say anything. Best of luck for your son, keep us updated!