Let me adopt the role of unsolicited political consultant for Delph. Here is the question: what do you do once your highly publicized political agenda has been derailed (the failure of HJR-3), and you follow that with a 24-hour twitter rampage that has received national attention, with an impending "big Monday announcement" amidst speculation that you will leave the GOP caucus? This is what you do...
Allow these public disasters to define your public transformation. This is political jiu jitsu. Do not double-down on your past political position, but rather, double-down on the disaster itself. Think of a recent example--Senator Rob Portman of Ohio, also vigorously anti-gay, only to discover his own son is gay, and subsequently made a very public conversion in support of his son, and in support of gay rights. Yes, there were doubting nay-sayers on the Left, as well as some on the Right who called him a traitor. But like a phoenix, a new Portman has arisen that can appeal to moderates in both parties. THAT is what US politics is about--the center, which usually holds.
Sen Delph--if you want to survive this catastrophe, then make it clear that your "twitter meltdown" was symptomatic of your mental anguish over being torn by your traditional beliefs on the one hand, but your personal knowledge of your brother on the other hand. Any "re-birth" is accompanied by trauma, and that was yours. Be humble, admit you were wrong, use your love for your brother as the foil to disperse the past sin (as opposed to using your brother himself as a publicity stunt). Now is the moment to lead, Sen Delph--if you are courageous, then you will find your way to the other side, and perhaps, even to another term.
(And yes, I know I mention neither lemons nor lemonade in this essay. I'm too busy watching Voyager reruns on Netflix to ensure consistent use of metaphor.)