Somebody should tell us, right at the start of our lives, that we are dying. Then we might live life to the limit, every minute of every day. Do it! I say. Whatever you want to do, do it now! There are only so many tomorrows.-Pope Paul VIHe didn't mean YOLO, in the popular sense. What he did mean was, if you want to reduce it that far, YOLOITHOTROTB, or You Only Live Once in the Hope of the Resurrection of the Body, because you should aim for Heaven, and you only have one chance, one life on Earth to do so.
I think he would agree that we should, instead of being foolish, we should live with joy, in pursuit of the good, the true, and the beautiful. We should partake in the Sacraments, especially the Eucharist and Confession. GO TO CONFESSION! It's awesome!