Since you have "about" in here, it forces the meaning of "how" to be "in what way." And don't say "about that..." in this context. It is awkward. Just say "thought how" or "thought that."
The word "about" here is a problem; When you remove "about," you can actually get away with using either "how" or "that." "How" has been in widespread usage in this way for years, so even if it is not formally correct, it is widely accepted.
"How" seems to have a valid usage here because there is a subtle difference between "that" and "how" in this context. "How" is more general, more vague, and more pensive; it becomes almost philosophical in its intent, and its connotations. (Another way of saying this kind of thoughtful usage of "how" is to put "about" back in and eliminate "how." The sentence then becomes "Tyray also thought about seeing Darrell's dead face." "Thought about seeing" and "thought how he would see" are equivalent.) Tyray is contemplating the action of seeing Darrell's face, probably imagining it and imagining how it will feel.
"That," on the other hand, is more focused on the action itself. If you use "that" in the sentence, it will mean that Tyray is confirming to himself what will definitely happen: He will see Darrell's dead face.