I think the reason he was like that with the pic's is that me maybe had a kid or kids that they resemble?
I mean, there was (obviously) quite a lot running through his head at that moment, Tyrese was clearly, if anything, (too?) introspective (for his own good?) Ultimately, I think he was just reflecting not only on his circumstances, but the circumstances of the world as it now exist.
When they were driving to the village, the kid told him that he had a mother, and two brothers, that he hoped were alive. Tyrese assured him that they were alive...so obviously coming face to face with the naivety of his optimism touched him in a way that he wasn't ready for.
I liked the character, and will definitely miss him...but I don't mind his death. It felt right, given not only his specific characterization, but also the (loosely) running theme of the program that only the strong can survive in this world. Dale. The Terminus people BEFORE they became cannibals. The presumably peaceful inhabitants of that village. Like Abraham said, only strong people are left now....Tyrese wasn't tough enough for the world anymore.
I don't agree with those saying that he "had all his character development right before he died"....Tyrese has had quite a bit of characterization.
I feel like he was one of the more developed characters in the show...we got to a point where we knew what he was about, we knew how he would react to certain situations, etc.
He started out moral, snapped for awhile after his girlfriend was killed, but he forgave Carol and he ended up doing this :
^ I loved this moment, because it said everything we needed to know about his character without actually saying anything.