Is it correct to say "we thank you for his contribution" instead of "we thank him for his contribution"?

Means: We appreciate your contribution to him; instead we thank _ What is his contribution?

I think that you want to know whether the meaning of following either (a) sentence or (b) can be substituted with each other:
(a) We thank you for his contribution==incorrect or misleading meaning, because the direct object of this sentence differs from that of indirect one. Therefore, it cannot be substituted or as an alternative to (b)
(b) We thank him for his contribution==the original sentence.
Yip

不一定