First of all, he is missing enchants on gear that he has had for a long time, has no professions at all and has a lot of catching up to do on his legendary chain. Jade Spirit is better than windsong wep enchant, and cerulean is better for disc than pearlescent leg enchant.
He is also wasting stats by gemming into and reforging out of same stats. What he could do is replace all his gems with int/mastery, spirit/mastery and mastery to bring a better balance to his stats. Then remove all his reforges, and just reforge out of haste and maybe some spirit into more mastery. This should increase his raid buffed crit and mastery by somewhere around 4% each, but he could still have almost 36k spellpower and over 10k spirit. There may be a more optimal setup, this is just a quick opinion.
Direct him to the following guide for more current info on his spec:
Here's what I'm doing for this fight specifically. During most of the fight, I just tank/spot heal, stay on top of regen, and try to keep up stacks of evangelism. I use a SW:P macro to keep my own crystal shell up, and I monitor the shell buffs for everyone by adding custom buffs in vuhdo (not set by default).
15 seconds before a stomp, I pop arch+IF+PI, then cap SS on both groups and PW:S anyone without a full shield. If SS is on CD or if movement prevents me from channeling it before a stomp, I will switch to inner will (for mana conservation), blanket the raid with PW:S, and switch back to inner fire. I have all the other timers turned off, because focus on the quake stomp timer is critical.
Right after quake stomp I will pop Halo to help with DPSing bats and getting a head start on refilling crystal shells. I haven't been using it before quake stomps, because usually our druid has no problem getting crystal shells topped off with rejuvs. My job as a disc is to just try and keep them from falling off.
So far my group hasn't successfully downed this fight on heroic because of issues with bats, but we are getting close, and are hoping to down it next week. We are 2 healing it instead of 3 healing though. Disc priests are not just about spamming a rotation of spells now. It is all about anticipating damage, well timed absorbs, and making the most of your toolkit.
Edited by Lifegutter on 8/24/2013 1:01 PM PDT