My sleep apnoea just requires me to pop a mask on before I go to bed.  But your circumstances may be different.

I put in a claim for PIP which was denied and now I am over 66 and on pension I tried for AA. Denied again.
I have other health conditions ( Diverticular disease and Bile Acid Malabsorbtion ) which I consider hard to live with and they refused all of them. I am able to dress, wash and feed myself and that's enough to exclude me from any benefits.

All I managed to get was a Blue Badge and that came from the local Council.