'Eureka' & 'The Dead Zone'
The traits that make a TV character a hero are not genetic; they can't be passed on to other family members. So many times we've seen the heroes of TV shows contend with siblings, cousins, parents, and their own children who are on the wrong side of the law.
And there are those heroes who never have to deal with their villainous kin because their paths never cross; they can be found on different TV programs.
Before Jack Carter was "promoted" from being just a US Marshal working out of the Los Angeles area to becoming the Sheriff of 'Eureka', Oregon, the Feds must have done a thorough and extensive deep background check on him.
And the fact that he had a megalomaniac cult leader as a first cousin probably didn't reflect badly enough on Jack personally to disqualify him for the job.
Nathan Carter set up his missionary compound on the other side of the country, in Maine. He took the name "Cyrus" and proclaimed himself to be the first prophet of the Book of Revelations. It was always Cyrus' plan to destroy the compound in a mighty conflagration, killing himself and all of his followers.
Thanks to the intervention of Johnny Smith and his power of 'The Dead Zone', all of the cult members were saved. Only Nathan Carter perished by his own wish.
For this Theory of Relateeveety, I made Jack and Nathan first cousins. There is a strong enough resemblance between the actors Colin Ferguson (who plays Jack Carter on 'Eureka') and JR Bourne (Nathan in 'Vortex', the latest episode of 'The Dead Zone') to think that they might play brothers. But 'Eureka' is still in production. As such, other family members besides Jack's daughter may show up in town, or they may be mentioned.
The death of a crazy cousin might pass unmentioned; but people would offer condolences and probably even inquire ghoulishly about the loss of a sibling; no matter how crazy they might be.
There is still a possibility that we might get to meet Jack Carter's dad some day on the show. So I can't go theorizing just yet as to who he might be. But perhaps his uncle, Nathan's father, might have been a hero from World War II by the name of Sgt. Andrew Carter ('Hogan's Heroes')......