for him/his seeing me off?

[Aleaf]

I wrote a thank-you letter to Ted for him/his seeing me off.
1) Does the sentence make sence?
2) if it does which word is more accurate-him or his?
Thanks ~~
_________________
Try to change youself before you try to change others.

[Conchita]

I wrote a thank-you letter to Ted for seeing me off sounds better. Otherwise, I'd say 'for his seeing me off'.