I also have an older brother that stutters as well and I have a semi severe/severe stutter depending on the day/week, I’ve always wondered if it was because I heard my brother when I was really young and just adapted that speech, but I was apparently born with mine like my brother. It does suck but you learn to live with it, you can learn tricks to get through the stutter and make it bearable. I use to know tricks but they just stopped working so I just feels with it when it gets bad and just rant to my fiance when I get the chance to get the anger out.