As for martial arts training, your priorities should remain the same. Train to stay healthy and to protect those you care about. And remember, the point of learning how to defend yourself is to make sure you return safely to those you love.
My friend's loss reminded me to let go of all those little things that bug me but don't really matter, and to focus in on the things that count. A great lesson, and one that I hope I can retain without needing another sad event to remind me.
Remember what and who is important to you. It's for them that we train.
Train with clarity and a proper spirit.