Phish,
I talked to my buddy who has Rotts and he wasn't very sympathetic to the dog...He agrees that you probably are prolonging a problem if you try some type of rehab.
I'm sorry for the trauma that this has brought to you and your family.
It would break my heart to have to make that decision for my dog.
It DOES disturb me to see how eager some board members are to discuss the method and equipment to use("Sheeatt Bubba....Git out yer Desert Eagle!)
I see it as a loved and trusted family member who made a big mistake.
Best wishes for your sons' recovery.