Attendance Allowance is one of the few handouts that isn't means-tested whatsoever, but is purely granted on need, even if that need is not met, and no one will check what you actually spend it on. So I guess if you're a multimillionaire you have to deal with your conscience on whether to apply or not. But few people are, and AA opens the doors to other things like Carers Allowance, council tax SMI disregard and various discounts like for example the WaterSure Plus scheme. So in the light of its possible abolition for new claimants, don't hesitate and get the application in now. There are various organisations that can help with the form, and they know what to put. You have to remember to fill it in with the worst day in mind and be brutally honest what the person can't do and has difficulties with, and also how long these tasks take them.
Carers Allowance is not means-tested in the way that your savings don't matter but you are not allowed to earn more than £110 a week. Basically they see you as doing this as a full time job of at least 35 hours a week so this should be more or less your only income. It's classed as a benefit though and not an income which is how they get away with paying you a paltry £62.10 a week, which is a complete joke if you've given up your career to look after someone. End of rant.