(In the quote above I've pieced the two things that seemed related and the bit you had in the middle of those two is quoted below)
So it seems the Border Patrol knew of the potential danger to the lives of people crossing the river and wanted to go to save them, and probably arrest them too.
They were blocked by the Texas officials who also didn't know whether the people were in danger or dead, and said to Border partrol that they would not be allowed in, even if people's lives were in immanent danger.
AFTER the fact: It turned out that by the time Border patrol had made it to the border of the park, this woman and her two children were already dead.
But this doesn't make the Texas officials look any better.
1. At least Border Patrol cared enough to try and save lives
2. Texas officials didn't care if people were in imminent danger or not, they weren't going to let Border Patrol in, even if BP could have saved lives.
In this case BP look like the good guys, Texas authorities look evil.
This doesn't help explain what was going on at all. Who is Collin Rugg? His post is light on facts and dripping with propoganda.
Also there is no factual explanation offered for what is going on in that video.