Have him feed him 30 to 40 3mg Melatonin a day, and just spend as much time around the animal that he can for awhile, a pen mate might help as well (one that is really calm).
He needs to continue to tie and rinse daily just not push the animal to fast, we kept ours in a 12*24 pen for the first week or so until they calm down, some took longer. We have found feed and water to be my best friend when trying to get them calmed, he needs to feed at the same time each day and stay around so the calf finds out that he is the good guy, and when he sees it is a good thing.
We had a HW that was like that, He would just get worked up and go off, (we knew he had some trust issues when we bought him, swelled up chin, but that is why he came cheap) we worked with him daily for about a month, we made progress but it was slow. The breeder said to try Glu-coat, it had worked in the past on some calves, about 2 weeks into feeding him the glu-coat, he just stopped, Tuesday, he was climbing the wash rack, Wednesday he just stood there from start to finish and was fine from then on out. (We did feed him the glu-coat for the entire project, but it was worth it)
It seems like some of them can test you more than others but scared calves can seem the worst at first. We had a Angus calf get out the day we brough him home, ran through the gate down the road and found the creek, I followed him for 3 hours until it got dark. Spent the next week tracking him in the creek found him twice just to see him run through junk I could not crawl through, after a about a 10 days being on the loose he found some horses to hang with and got trapped in a pen by the horses owners, we had to have him roped and loaded in the trailer. He spent 3 days in the trailer, we waited until he stopped blowing snot and bouncing off the walls to move him into a corral, he was haltered and getting rinsed a week later. Food and time is all it took.
Tell the boy, it is up to him, he needs to be patient and persistant, and always keep his cool, At least it is a long project and times is on his side.