Concept:Tracing family tree step-by-step to find the relationship.
Explanation:P is Q's brother, so both are brothers.
R is Q's mother, so R is also P's mother.
S is R's father, so S is P's grandfather.
T is S's mother, so T is the mother of P's grandfather.
Therefore, T is the great-grandmother of P.
Since P is male, P is T's great-grandson.
Answer:Great grandson