Lucy, I see my own journey with my beloved Liberty, so similar. Yes, do try the Gabapetnin as it may give him some relief.
Now, know that what I'm going to say next may sound cold and heartless and it's the exact opposite. It's said with love and deepest support.
Consider the time of year. I had planned my Liberty's departure for December 16 (2013) carefully. The semester was over so I didn't have to hold myself together to get work done. But it wasn't so close to Christmas as to make very successive yuletide "that time".
A kiss on the nose of Spirit's lomg smoot.