Cousin Roger... Yeah. Bo and Luke mention when their folks passed on, in Season 6 A Boy's Best Friend. Little Terry Lee is so sad and down from losing his folks, that conversation goes like this. Bo:"Kinda brings you back, don't it Luke?" Luke:"Some how, I don't remember bein' quite that sad." Bo:"Shoot, we were awful young when our folks passed on." Luke:"I guess it's 'cause I had you an' Daisy." Bo:"An' we all had Uncle Jesse." Luke:"We gotta count our blessings." Bo:"That we do."