Sounds like he's an Incantrix with abrupt jaunt.
To Clarify, Abrupt Jaunt is INT mod times a day, so probably like 7 times a day in your wizard's case. It's an immediate action, so it can be out of turn HOWEVER it uses up your swift action for next turn, so he cannot dodge 2 attacks with it a round. It's also only 10ft, so reach can help, or AoE spells.
For example, a fireball centred on him will still hit him no matter where he teleports.
A Large Creature with a Spiked Chain will miss the first attack, but the secondary attack will still work, if this creature has mageslayer it will also prevent him casting.
An archer will miss the first arrow, but rapidshot and all that means the second, third and fourth will be on target. A splitting bow means that your wizard dodges 2/8 attacks, he still gets 6 arrows in him.
Abrupt Jaunt is AMAZING, but it's not exactly an I Win button.
8th level spells as a level 13? I mean yeah, a 7th level spell empowered would be 9th level, even if you reduce empower to a +1 so it occupies an 8th level slot, he cannot cast that... he doesn't have an 8th level slot to expend.
I suggest going through his character sheet with him, ask him what allows him to do what and where he is getting it from... if he's using out of date material and cherrypicking from 2 different classes then obviously he's going to seem too powerful.