“... his life, humanly speaking, ended in failure...”
There is nothing wrong with that statement. Don’t change it when you quote it.
His statements about the ROP are wrong, stupid and show a fundamental misunderstanding of the beliefs of the ROP.
It’s wrong if that’s where he left it. Did he go on to explain that spiritually speaking it was the ultimate victory? Not everyone who hears his words has a clue. To leave as a takeaway message that, even just humanly speaking, the cross represents failure, is unspeakably misguided.