one of the horses i ride does the same thing when putting on the bridle. i just wrap my arm around her face and hold her head down.
put your pointer finger on side the middle of the ear (not on the outside on the inside , not in his ear)and he should put his head down
Work on putting on and off his halter, do it in smooth motions and don't react if he starts to toss his head, eventually he should begin to get used to the halter being taken on and off. If he is not getting any better with this I would put the halter on (rope halter may work best) and hold steady pressure directly down until he gives, reward and take it on and off
Hope this helps!
Hold his head down. Wrap your arm around his face and put your hand where the nose band should be
Short your reins and press carefully your legs. Stay in circles and do half-half. Every time half goes correctly and the horse response make sure you clap your horse :-)