You and your sibling are anomalies if you are telling the truth (which I doubt). It is rare and generally means the psychological screening done before allowing the treatments such as surgery failed them. Why don't you read this article so you have some facts rather than your wacky anecdotal crap.
How Many Trans People Regret Transitioning? On average, 97% of people who are transgender are happy with their decision to transition. Only ~3% ... Difficulty of Transitioning: 33% Financial Reasons: 3% Medical Reasons: 2% Family Pressure: 26%