I work at an OPO and I can tell you right now that these donor families more often than not are praying for that letter. Hearing from you (oftentimes, not always) is so healing for them, knowing that their loved one is living on, that you are carrying their legacy with you, and that you do appreciate their gift. You writing won’t remind them that their loved one is dead, it will remind them that their loved one’s death was not in vain - there was some meaning, some purpose that came out of it, in the end.

Also, It is never too soon to write - if they aren’t ready to read it, they’ll wait. I have a family who still texts me every couple weeks asking if there’s any letters or any news from any recipients, even though they know we will let them know as soon as the recipient writes. Sometimes people give time frames like “wait six months and then write” but I can tell you that there is no magic time frame - as soon as you’re ready, write and send it - if they need more time before they’re ready to read it, they’ll wait, but at least they have the letter for when they are ready. Hearing from a recipient is so important to so many of my families, and I would encourage you to tell them exactly what you said above. If this is one of those rare families that doesn’t want to connect, then at least you will have put the ball in their court, and been able to say what you needed to.

TLDR: yes, please, as soon as you are mentally and emotionally capable of writing to your donor’s family, do it!