It sounds like something has triggered an anxiety disorder with the spraying issue. There are certain anti-anxiety drugs for kitty's that stop this in as little as a couple of weeks, depending on the problem. They tend to make kitty very sleepy for the first couple of days but that is normal. If your budget it tight, there are other possibilities to try also. When you see him doing this, you must take him and confine him in a very small space with a clean litter box and wait until you see him urinate in the box, then let him out and give him all kinds of attention. By doing this, he'll know he gets ALL of your good attention when he potty's in the box. If this does not work, you can keep him in a different room with no other cats and a clean litter box for most of the day, visiting him often, and let him out when you can be right there to supervise him 100%, and put him back in the room when your leaving or his free time is up. Even though your cats have been together for a long period of time, sometimes the other cat can upset the (naughty) cat because of something simple and it triggers this problem. He is acting out and being distructive is the only way he can deal with his feelings.
Good luck, this can be very frustrating a may take awhile to straighten out, so you must be patient.
Jenn