To be able to claim PIP, you must have a long term health condition or disability that affects your ability to function as a person without your condition does in everyday life.
The amount you get depends on how your condition affects you in your own personal circumstances, not on the specifics of the condition you have.
It can take up to four months from the date you started your application to when you get your money, so as soon as you think you need PIP, you should put in a claim.
However, if you are terminally ill your claim will be processed quicker.
There are no restrictions on how you can spend your PIP money, and you do not have to spend it on paying for the care that you need.