Having a friend do the euthanizing for you is a very good option.
I put my beloved avatar roo (Jack) down last weekend. I had asked my husband to do it for me, b/c Jack has been with me for 4 years, and obviously was a favorite. But, in the end, I chose to do it myself, while having hubby stand by to help if needed, simply b/c I would rather do it myself than stand by and watch someone else do it, and perhaps not do it swiftly. Hubby was good support and helped me simply by being there, and providing a second set of hands.