I've also posted the link to that article here, but I never claimed I agree with all its claims. It should be used not differently than any other source on the internet, with enough grains of salt: I simply remember the "uncle" connection and I remember reading about the connection, and I've searched for any article mentioning it, finding the article you criticize.

There are, however, still other ways to read about the same "uncle connection", especially about the uncle's father in law, searching a little more. E.g. Wikipedia article, the current state:

https://en.wikipedia.org/wiki/Graham_E._Fuller

"After the Boston Marathon bombing, it was revealed that Fuller's daughter Samantha Ankara Fuller (married name Tsarnaev) was married in the 1990s to Ruslan Tsarni (born Tsarnaev), the uncle of the perpetrators Dzhokhar and Tamerlan Tsarnaev.[16] They divorced on 26 April 1999, in Orange County, North Carolina.[17] Ruslan Tsarni worked for companies connected to Halliburton. He was also a consultant for a company contracted by the U.S. Agency for International Development (USAID) in the former Soviet Republic of Kyrgyzstan.[18]"

Fuller is somehow still relevant internationally (as of 2018)(!), enough that he's a topic for "BBC in Turkish" news:

https://t24.com.tr/haber/eski-cia-yetkilisi-graham-fuller-ha...

Translated by Google Translate:

"BBC in Turkish

Former CIA official Graham Fuller on the arrest warrant

As part of the investigation into the July 15 coup attempt, former CIA National Intelligence Council Vice President Graham Fuller was issued with a warrant for the arrest"

It's about arrest warrant in Turkey if I understand correctly. Here's an English version:

https://www.bbc.com/news/world-europe-42198399

and Newsweek 2017:

https://www.newsweek.com/cia-graham-fuller-arrest-turkey-erd...

Anyway, back to Tsarnaev case, there is a proof that while living in Fuller's Maryland house, the uncle of the brothers, at that time also still with the family name Tsarnaev (he changed it later to Tsarni) in 1995 incorporated there in that very house "the Congress of Chechen International Organizations":

https://www.madcowprod.com/wp-content/uploads/2013/04/maryla...

https://www.madcowprod.com/wp-content/uploads/2013/04/DC-rea...

Fuller didn't deny these facts, even if he claimed in 2013 that it was somehow accidental:

http://backchannel.al-monitor.com/index.php/2013/04/5090/for...

"“Samantha was married to Ruslan Tsarnaev (Tsarni) for 3-4 years, and they lived in Bishkek for one year where Samantha was working for Price Waterhouse on privatization projects,” Fulller, a former CIA officer in Turkey and vice chairman of the National Intelligence Council, told Al-Monitor by email Saturday. “They also lived in our house in [Maryland] for a year or so and they were divorced in 1999, I believe.”"

He also commented on Turkish story here:

https://stockholmcf.org/graham-fuller-i-am-lucky-not-to-be-l...

"Fuller added that “Not content with absurd accusations of coup plotting by myself and a few Americans, the Erdoğan government has also stoked the fires with ‘fake facts’ and crude propaganda fabrications about my own views and writings."

So yes, not everything that is written somewhere is true.

Still, an interesting person. A lot can be found using a search machine.