Has he been to the vet recently? Is he neutered?
At 12 years old Frederick-Douglas should be in for a yearly or twice yearly exam w/geriatric blood panel including T4 & urinalysis to rule out any medical concerns including liver, kidneys, thyroid, FLUTD, urinary crystals etc
First rule out any medical issues, next step is to determine if this is stress related as obviously there has been some upheaveal in his life from early on, shifting houses/families a few times.
How does Fredrick-Douglas get along with other pets especially any cats in the house? Is he harrassed by another pet? Do all the animals have areas they can escape to for some down time alone?
Is he being ambushed near the litterbox by others? Is the litterbox near noisy appliances furnace, washer etc that may have come on suddenly & startled him? Or is it in a high traffic area like an often used hallway?
Is he being scolded/yelled at or otherwise punished for going outside the box? This will only re-inforce the peeing in places like corners/behind furniture so he can't be seen eliminating.
Are the litterboxes all uncovered? Have you tried a covered one?
Have you tried Cat Attract Litter
How many litterboxes do you have? General rule of thumb is one box per cat plus one extra ie 4 cats = 5 boxes
Next is this behavioural or a learned behaviour?
What are you using to clean the pee spots with? Any cleaner with an ammonia or bleach base smells very similiar to the base ingredient in cat pee which will only reinforce his peeing in that area to cover the other smell with his own.
An enzymatic cleaner such as Nature's Miracle or the home made version = 1 cup water + 1/4 cup vinegar + 1/4 cup rubbing (isopropyl) alcohol, mix together in a spray bottle. Mop up the pee, spray area w/vinegar mix, mop up & spray area again let dry. This will remove the ammonia smell that you may not be able to smell but the cats certainly can.
If the area is not cleaned enzymatically the cat will repeatedly use the same area as they can still smell the previous pee there so it's territorially a good spot to go.
Is he peeing or spraying? Spraying usually involves vertical surfaces where the cat backs up against & often you can see the tail straight up twitching while he sprays pee 6-8" up off the floor against walls/furniture.
Is this in reaction to an unneutered male or unspayed female in heat in the building/neighbourhood?
Are there new people/pets in your home or has someone recently left?
New carpet/furniture? Did you re-arrange the furniture? Changed laundry detergent/household cleaners added something with an ammonia base or strong smell - flowery or otherwise?
Does he have a high cat tree where he can see out the window, interactive cat toys to amuse himself with, do you play with him using a feather wand type toy?
Have you tried Feliway pheromone diffusers/sprays? If sprayed on the area a cat has previously urine marked (after cleaning w/an enzymatic cleaner) it may reduce the likelyhood of the cat returning to urine mark that particular spot as it now has a pheromone marker.
You may need to go back to the basics of litter training as it seems this has been allowed to continue long enough to the point that Frederick-Douglas may think this is acceptable behaviour - unless it is medically related of course.
Your vet may be able to help with behaviour modification medications if necessary http://www.marvistavet.com/html/body...e_soiling.html
Honestly giving him up is not going to solve the problem especially if he craves human attention/interaction, it's just passing it on to someone else and bringing a cat that is urinating outside of the litterbox to a shelter is usually a death sentence even if they are a "no kill" as that only applies to adoptable animals.