He definitely should upgrade all his gear if he wants o keep going. Every upgrade is VIT (left side) and MND (-> DPS and Heal increase!).

A11S will have some heal and HP checks (Photon and few sec after AoE damage) and he should be able to survive. I had 20k HP on my first clear and had to increase my HP pool with gear and another VIT meld (I use 3) to have around 22k to not go splat in A12 progression as easily.

My set I use (or very similiar)

http://ffxiv.ariyala.com/X3TR

The relic is not needed as you can reach acc cap with melds on ur gear and food anyway but the 270/275 non relic options are crap anyway for a SCH this tier so may as well go for it.

In general to the topic: if he doesn't want to upgrade he doesnt care enough for the team as any upgrade makes it easier to pass HP, DPS or heal checks.

Hope you manage to convince him else... I fear you should look for somone who is willing to invest a minimum :-/