L.J.
Re: the spitting. You could try my tack: when the spitting happens and the following ick that coates his face, get a COLD damp washcloth and mop that little mouth. Then hand him a damp cloth and walk him through cleaning off anything he may have spat on. Kids get tired of that routine, especially if you can be persistant and consistant with the firm admonition that "Spitting is a messy, dirty thing that needs to stop." I know he's a boy and dirty is cool, but it might work.
For the TV thing, I would heavily restrict what he watches. Nothing of what sister is able to watch, and certainly nothing that might frighten him. It's hard, especially with a protesting adolescent, but it can be done. If he has a favourite DVD, consider getting a cheap DVD player and hooking it up to the stereo--that way he can listen to things like a radio program without the frightening or startling imagery. Four is still a bit too young to grasp reality from fantasy.
Best of success!