Tyrone Simpson, known better as Uncle Tyrone, is a cynical elderly Simpson relative who lives in Dayton, Ohio.
Judging from his age and appearance, he is most likely Abe's big brother making him a great-uncle to the Simpson family.
The family intends to visit him during his birthday.
When the Simpsons were singing "Happy Birthday" to him, he said "Why won't I die?", judging from that, we can most likely presume he is bitter and depressed.