Parsers are against ToS on FFXIV because they don't want people judging others over doing 10-30 DPS lower against someone doing 100 DPS lower. This does not mean a carry if they are attempting THEIR BEST.

If they're trying their best, and the party wipes due to not meeting a DPS Check(i.e. Titan EX, Bismarck EX), then the best someone can do is give them tips, or if possible at the very least ask if they're on the same server so they can help them improve.