Soooo glad you've written them! I am also part of a three time donor family... all three were tissue, bone, and cornea donors. Since it wasn't my immediate family (in-laws) I didn't expect any correspondence. Knowing that they helped others through their donations was enough of a gift for me. I would love to think that they became donors because of my experience, but that doesn't really matter. They did it!
Some families never write back because the death may have been tragic. Deaths by suicide, gunshot, or car accident are often the reason families don't write back. Their trauma is just too raw, and reliving it too painful to write back. I was blessed to meet my donors daughters. Something I will always be grateful for!
Have a blessed day!
Joe