Sounds like he is waking after one sleep cycle and is unable to get himself back to sleep. I have found this VERY common in children who are rocked to sleep and who bedshare. If they don't put themselves to sleep all on their own at the start of sleep they are unable to put themselves back to sleep when they wake after a sleep cycle.

I don't know that I have anything more to share than what you have tried. Have you tried not going at all when he does wake. Maybe your good intentions are just fueling his fighting going back down as he sees you and is accustomed to having outside help when an adult is in sight. It will be hard for all but maybe try a couple weeks of not being near and not going to his aid when he wakes. He might just decide it isn't worth being awake and go back to sleep.