Who sits opposite to the one who sits immediate left of R?

1) A sits 2nd from one of the ends.
2) E's mother-in-law sits opposite to the one who sits 3rd to the right of A.
3) One person sits between A and her sister-in-law. Therefore, A is female.
 
4) Three persons sits between B and the person sitting opposite to Q's father.
5) A’s son sits immediate right of A.
 
6) C and D are unmarried. Therefore, neither C nor D is an immediate neighbour of B and so E will be A’s sister-in-law.
7) C does not sit next to E. Therefore, C would be at the corner and D would be A’s son.
 
8) B is married to E who has one child. Therefore, B is male.
9) B’s father faces A who has two children one son and one daughter.
 
E is sister-in-law of A. Therefore, B is the brother of A.
10) R faces immediate neighbour of A’s niece. Therefore, C is A’s niece and daughter of B and E. We also know that R is B’s father.
11) R sits to the right of T.
 

12) P and her granddaughter Q are not sitting together. Therefore, case I will be cancelled.
Clearly S is Q’s father.
 
13) Q is married. Therefore, T is the husband of Q.
The final solution is,
 

 Hence, D sits opposite to the one who sits immediate left of R.