I don't like to push them until they fail, I believe that destroys anyones confidence, human or horse.
I want them to be successful every time I work with them so tend to ask very small questions initially, perhaps after schooling just walk to the gate and back while cooling off, when he can do that without flinching gradually build on it from there, always set a target in your mind so you don't get carried away and push it, so perhaps your next step will be the 2nd lamp post down the road. If you do ask too much and he wimps out
don't ever stop, just quietly get him to relax, then go a few more steps/meters/fields before turning back, he must never associate the bad behaviour with getting to go home
You can help him gain confidence in company by changing his position in the group, at the back he's a follower who just does what the others do, if you bring him to the front he's then got to put his big boy pants on and be the leader which will help set him up for when he's solo
its nice in a group as he can start out with leading for 10 seconds before dropping back and letting him absorb it for a few minutes, then go up front again for a little bit longer and so on until he can lead all the way without wobbling