Now I know 100% you're talking out of your ass. The Al Khalifas rule Bahrain. The Al Thanis rule Qatar. That bloodless coup you were talking about? That was the father of the current Qatari emir deposing his father when he was abroad (https://en.wikipedia.org/wiki/1995_Qatari_coup_d%27%C3%A9tat).

The current emir succeeded him peacefully after the father stepped down.

All Arab families are intermarried in various ways, but the Al Nahyans have always been historical rivals to the Al Thanis, and have always tried to invade Qatar. The Qataris were invited to join with the UAE, along with Bahrain, but refused because they figured Abu Dhabi would take the leading role eventually (which it has). In all of the UAE, only Dubai remains more autonomous than usual because they were able to develop on their own with the guidance of the current sheikh of Dubai.