Inappropriate scratching can be corrected, but it takes time and work.
No one on this site will support a decision to declaw, and kudos to you for wanting to find an alternative! In fact, you may want to help educate your mom as to why so many countries around the world have made it illegal because it is considered cruel. http://www.thecatsite.com/Care/34/De...-Manicure.html
The best "quick" solution is Soft Paws: http://www.softpaws.com/
Here is an article about how to help your cat scratch appropriately: http://www.thecatsite.com/Behavior/5...o-Stop-It.html
Deterrence is a big part of correcting inappropriate scratching. We covered our chairs and couch with throw blankets. When company comes over, they fold up and go in the closet - an added benefit is that the furniture was also cat-hair free ready for company.
If the problem is the back or sides of the couch, tape aluminum foil over it. That worked for us and was cheaper than the tape things they sell. Those do work, but they're expensive.
I would also suggest your family purchase Feliway spray. Spray the places he's been scratching he shouldn't with it. Even better if what he's been scratching is covered up with aluminum foil or tape or something - spray the Feliway on that. Feliway is a synthetic hormone that mimics the "friendly" markers in cats' cheeks. All of the scent glands on the head are "friendly" markers - all of the other scent glands are territory markers (paw pads, pee and poo, and anal sacs). Getting the "friendly" scent on places he's been scratching will help redirect his behavior.
Try different types of scratching stuff. Get some that are flat, some that go up, different materials - cardboard, sisal, carpet, &etc. Some cats like those horizontal cardboard things. One of our cats loves the scratch pad - but the side that is that soft mat kind of stuff as opposed to the sisal side.
The others love the cat tree.
Also, keep his claws clipped to the quick. This really helps minimize the damage from scratching.
Cats LOVE to stretch and scratch when they wake up, so having the scratching stuff in the right place is important.
Is the family willing to buy a cat condo or cat tree(s)? These - we found - REALLY help, because then kitty gets his/her own furniture - and they can stretch and scratch to their heart's content after a good nap.
In discouraging your cat from scratching in the wrong place, when you catch him doing it, whoever in the family sees him doing it should blow a short, sharp puff of air directly in his face, say "no," and move him to an appropriate scratcher.
Also, cats learn better from positive reinforcement than negative reinforcement. So any time someone sees him scratching where he SHOULD be he should get praised to high heaven and given a treat or something.
....but keeping claws well clipped, putting up "deterrents" in places he's been scratching he shouldn't, spraying Feliway where he shouldn't scratch, offering him lots of appropriate alternatives, and praising him a LOT for appropriate scratching should work. It doesn't work overnight. Think of kitty as a 2 year old - it'll take weeks or months to change behavior that's already been "set." But it can be done if everyone in the house is consistent about it.