6 year old cocker spaniel

Question
Hello :)
I saw this online and I thought I would give it a try. I'm actually writing on behalf of my mom, who is the owner of this dog (a 6 year old cocker spaniel). Her dog is extremely dominant, definitely the alpha of the household. She will not come when called,but will sit and down at the drop of a hat,  and she will not let you pet her over the head. She has always had issues with not going to the bathroom outside like she is supposed to, and to be honest my mom has had it up to here with her and it starting to resent her, as she has ruined several carpets in her home. My mom took this dog to puppy kindergarten, and basic training classes for approximately 4 years. This dog (casey) is EXTREMELY food motivated, she will do ANYTHING to get food or what she thinks is food. (she actually once ate a tube of desitin.  And if you leave something on the counter forget about it she will jump up there and eat the whole thing, even if it is a full loaf of bread.  Anyways,back to the potty training issue, she knows how to get her to go outside, she will take the dog to go outside, stay out there with her for 10 minutes or longer casey may pee but wont poop, brings her inside, 2 seconds later she poops in the house, or vice versa. It is like she is doing it to actually be defiant.   It is extremely frustrating and my mom is constantly complaining about her and how she wants to get rid of her ( I know she wont because she loves her anyway) she is just upset) My mom knows the whole take the dog outside when she goes praise her in a high voice, and when she does go in the house she picks up the poop/pee takes it outside puts it in her "spot" and tells her this is where she is supposed to go.  I recently have been speaking to my mom about getting a dog training collar basically because she doesn't know what else to try. I figure if the collar makes her listen to commands like "come" maybe she will start to listen about going outside.  Honestly she has tried everything,even the halti which does bring down her dominance level a little bit but wont help with the peeing and pooping, she takes her outside every half hour but she somehow manages to go in the house sometimes. My mom has removed, bought new carpet, and sprays with simple solution every time she goes in the house.  She was so happy with her when she was a puppy, now she just seems like a burden to her and I don't want her to feel that way towards her, she is her pet she should enjoy her and casey in turn should be enjoyable. I really would appreciate any help, as I said she is at her wits end. Thank you!

Answer
Hi Kelly,
For the housebreaking, I recommend that your Mom try crate training her.   A dog is never to old to use this method.  She will be basically starting from scratch but if she does it correctly, I am sure she will be quite pleased with the results.   They key for your mom to remember is that if she is able to eliminate the opportunity for accidents for a period of time, the dog will learn to go outside.  The crate is the easiest way to do this.  If you can not supervise the dog 100% of the time during the initial stages, than the dog should be crated.  You may even want to go so far as to keep the dog on a leash while not in the crate.  That way if they start to have an accident, you give the leash a gentle tug and go immediately outside.  Of course we recommend a nice sized open wire crate.   For preferred crating recommendations, go to:
http://www.paw-rescue.org/PAW/dog_tips.php
Look for crate training.
If you take a few moments and read thru the tips you will find tips for all of the "issues" you mentioned above.  It sounds like your Mom would benefit from reading them.