First off, I am truly very sorry to hear that you lost your stepson.
I know it hurts so much when anyone close to you dies, and it may take a long time to find a new normal life. In June we lost my cousin the day after his 23rd birthday. My aunt is devestated, as are we all. Sometimes it doesn't even seems real quite yet, but other times it feels like we lost the world. Very difficult to deal with.
As for your other sons yorkie, I hope that things work out for the little guy. I hope his vet takes good care of him and hopefully it isn't too serious. My thoughts and prayers will be with him to pull through, and with the rest of your family until we hear good news! Good luck.