All in the family series

Maybe the reason you're struggling is because you don't have a news hook. Have there been incidents involving coach/parents and their kids and/or siblings? Accusations of unfairness? A coach dad who beat the hell out of his son on the sideline? The mere existence of dads and moms coaching their kids at the high school level is hardly unusual.

On the other hand, is this a more practical series aimed at parents who might be coaching their kids at any level, pee wee on up? Advice from coaches who have been there about what to do, what not to do? How to handle it when someone accuses you of favoring your child? How to compartmentalize the parent/coach role?

You need to have an angle sharper than "coaches coaching their kids/siblings on the same team" before you jump ahead.

 

One more angle you might take is if you found anyone who choose not to coach his own son and then contrast that with the one's that do. Three or four years back, a paper in my area, I didn't work there, had a story on high school coach who was the school's basketball coach. He had taken the school to the state's final four a couple of times. He left the school he was coaching at before his son entered his sophomore year and joined the varsity. He changed schools keep teaching and became the baseball coach at the new school. The story detailed how he had friends in coaching who had coached their sons and told him if they had to do it over again they wouldn't because of the problems it caused for the coaches with the other players on the team.