To solve this problem, we need to determine the seating arrangement for seven boys: P, Q, R, S, T, U, and V, who are sitting around a circular table facing the center. We will place them step-by-step based on the given conditions.

1. Placing R: Start by placing R at any position, say the top-most position considering it as 12 o'clock for reference.
2. Placing V: It is given that V is second to the right of R. Since everyone is facing the center, V will be placed two positions to the right of R.
3. Placing U: U is to the immediate left of R. Place U one position to the left of R.
4. Placing P and T: It is mentioned that P is third to the right of T. For now, leave these two positions as placeholders.
5. Placing S and Immediate Neighbors of Q: S and T are the immediate neighbors of Q, meaning Q should be between S and T.

Now, let’s align this information with our seating plan:

• Since S and T are around Q, and P is third to the right of T, we first need to place T.
• Trying possible positions for T and P:
• If T is placed at the immediate right of U, then Q cannot be placed as immediate between S and T considering Q has to sit exactly between S and T. So, skip this arrangement.
• There should be a better fit for such position alignments between U, R, V, and the rest.

Through trial and error on positioning S and T next to Q, we get:

• If T is placed at the immediate right of V, then P, by default, should be third to the right of T. Count three seats right-wise from T to place P, which would align all conditions logically.

Thus, the fixed sequence becomes: U - R - V - T - Q - S - P. Here, Q is between S and T, completing all given criteria.

Conclusion: Therefore, the person sitting on the immediate right of Q is T.