Tips on keeping baby asleep?

I'm having trouble with my baby standing in his crib every time he stirs, which wakes him up completely and he realizes he's alone and bawls his eyes out. He literally sleepwalks to the railing and climbs up then wakes up. So it takes me 2 or 3 tries to get him back to sleep in the middle of the night and its exhausting and frustrating as hell. I've been doing CIO but it doesnt work at all because he seriously just stands in the crib forever. He never falls asleep on his own. I have to rock him to sleep every time.