Aside from their use or not of sharia law..
They do seem to think they can create their own court system, outside of the normal Texas judicial system??
That alone should get the state & local DA's 100% attention..
I have not hear of any "local" private courts for some 130 yrs. Judge Roy Bean was established in the 1880's, over in Val Verde County, Texas. He was at least appointed by the governor, at the request of the Texas Rangers. He jurisprudence may have been questionable, but he was legal.
Also, I would add federal, but that's a no-go dead-end.. berry is probably encouraging Al Sharpton to help establish these courts.