Wow, what a bad news, good news, bad news update.

I'm sorry to hear Edgar has Feline Leukemia, but I'm so glad your sister's boyfriend's aunt will be taking him. Being an only cat with an adoring owner will be the perfect life for him. I'm so glad you kept him separated from the rest of your kitties until you found out he was not healthy. This could have been a disaster, but instead has a happy ending for Edgar and his new owner.

And I'm so sorry to hear about Buzz. Three years old is way too early for a kitty to have to leave. He sounds like he was a real character though, and you should have many happy memories of him and know that he is now hamming it up for everyone at the RB.

The only thing I can think of to cheer your sister's boyfriend up is...well....get him another kitty! I really believe this helps because it gives devastated owners something else to think about, and another little soul to care for. So it's not that they forget about the one that just passed, but they transfer their energies into positive things for the newcomer instead of into feeling sorry for themselves.