I don't think anyone who murders another person is cognitively intact.

They don't put intellectually impaired people to death, but they sometimes make them President.

I'm shocked that he did not get the death penality since he is black.

His crime was horrific but I feel the death penalty is inappropriate and we must do away with it and the only way to do that is to say none at all.

Intellectually impaired or not HE knew he was going to MURDER them, he knew enough to go fully prepared, he knew enough to know that killing someone is a CRIME, he knew that they were innocent people, behind bars for LIFE without hope of parole still means HE get to breathe, eat, sleep, walk, talk, etc, etc, even though he is behind bars BUT his victims get nothing more than a wooden box and a hole in the ground AND NO future except as food the worms, etc.
In cases like this I fully support the concept of 1 life taken = 1 life must also be given up in compensation.
And with his heinous crime, give him the needle BUT only enough to get him to brink of death, then bring him back again, do that for EVERY life he took and then give him the full dose and wipe him from this planet permanently with the final injection.

What difference does it make that he's mentally impaired? Anyone who murders eight people isn't playing with a full deck. Texas should execute him.