Disability allowance has become very strict indeed over the last couple of years. You can blame the ones who abused the system for that, claiming they are too ill to cope and living/drawing their benefits in spanish resorts. Basically you have to be very limited physically, such as not being able to walk more than a few yards before being in discomfort. Discomfort can include shortness of breath. It is not unusual to be refused three or four times in a row, but keep appealing. This is their filtering process. They believe those who are not really ill will give up trying to claim, but the genuine ones will persist. If finally accepted, it will be back dated.
I didn't say this, but you have to exaggerate on your claim form. If you can take your meds, if you can cook, if you can wash yourself, if you can dress yourself, then you are considered quite healthy. They don't care how hard it is, just that you can do it.
If you are married and your wife earns less than £90 a week, and has to look after you for a min of 35 hours a week, she can claim carers allowance, which is different to attendance allowance. However, you must be getting disability first. My wife had a stroke and was paralysed for months down one side of her body, has been getting cancer care for many years was refused. While in life support, they were pestering me to get her to their office for a job interview. You have to be tough with these people and I fought them all the way. I even got Citizens advice involved and in the end they gave in. The system is being governed to try and cut the financial deficit, but the government said it wouldn't affect the sick or poor. Those are the only people affected so far. So keep trying, form after form, send them in and get letters from Doctors to back up your case. You will get there.