I agree with Rick...I went through something similar years ago.
I had a coworker years ago that decided after his 3rd divorce (yikes) to sell everything he owned and start a new life in Texas. He sold me a decanter that was in the shape of a train locomotive for $5. I searched but could not find squat for information on the decanter, except that it was from a small company that no longer exhists. Another friend suggested I take it to a gentleman in Denver that owned a liquor store and was known to be an expert on decanters (he has a huge collection). The gentleman was very nice and said even he didn't have one, but if I wanted to sell it to him, he would give me $300 for it. I still have the decanter, but I quickly mailed off a check to my former coworker in Texas for $150. He really appreciated the money (it cost him alot more to move than he had planned), and we are still friends to this day.
Besides making my former coworker happy, I can still look in the mirror and know I did the right thing.
An extra few dollars in a Christmas card like Rick suggested would be a really nice gesture in my humble opinion.