If it was me I would go back to basics! Lots of lungeing with neck stretcher, side reins etc to get him used to contact without thinking about the rider then start lunging over some trot and canter poles, free jumping if you can, etc so he can figure it out on his own then think about you in the saddle!
For 1. Not all horses are taught to accept the contact. And if they are they will respond to different aids. First they must be forward and working from the hindquarters. Then make sure you aren't 'see sawing' on the reins to ask him down, this will cause discomfort and even tho it will sometimes result in the horse lowering it's head from pressure it will not be properly on the bit. Try getting him to stretch his head down to warm up etc. Gather him back up during your ride and give your inside rein little squeezing to ask him to lower his head.
2. As above ☝️ checking he isn't uncomfortable or sore is good. Also make sure you aren't coming forward before the jump, keep your shoulders straight until he jumps and you come forward naturally. Also make sure you don't take your leg off and your reins are even and tight enough that he know you are there xx
I’m not sure about number 1, but for number 2, make sure nothing is uncomfortable for him, both physically and mentally. Mentally speaking, make sure the jump is small and give him tons of praise and reward if he does go over. It could be that he doesn’t like jumping, the rider, or he had a recent accident or something that shook his confidence.
Hi Ashley, I would recommend possibly getting the horse checked over by a vet and also a saddler who is also trained in bit fitting to see if there is anything uncomfortable happening, hope you get this sorted😌