[Baz]

For sentimental reasons I would write a nice well thought out typed letter expressing in your heart-felt terms how much his actions meant to you and your family.

That letter will mean more to him than anything else.

Then include a thank you card.

Then include a restaurant gift certificate - so he can take "his" family out as a token of "your" family's appreciation.

That is how you say thank you in a special way.

You are a good dad and a good person. Nice to hear of your involvement. Thanks for making my morning 55.