The brother thing.... I'm sure Willie Mays had a brother who couldn't cut it in the show either. I don't think there is all that much you can extrapolate from Jeff to Jered, other than perhaps that he's genetically blessed perhaps to not have injury issues. They both throw with similiar motions, though Jered hides the ball better, and Jeff has pitched every 5th day for the last 7 years.
The major difference is, Jered is consistent and Jeff isn't. Jered has a focussed machine-like demeanor on the field and Jeff tend to get too emotional and that makes him usually get in trouble.
Jered's "tendinitis" was rumored to be (A) made up to publicly justify the two miinor leaguers we brought up for starts last week. The Angels GM is trying to deal and he was showcasing those two pitchers for other GMs.
(B) Jered was drafted two years ago and held out till just before the last draft, thus, he didn't pitch any games last year, and the Angels are reluctant to put 200 plus innnings on Jered's arm this season, and his "tendinitis" happened to coincide with the AS break, so he he a good long break in between starts.