As somebody on disability for psychological disability reasons, you're usually allowed to have somebody else fill those out for you. That's what I had to do.

Luckily the ones they send you afterwards every few years to check if you're still disabled are much shorter, and if you've got a detailed medical record of your disability sometimes they can't shut it off no matter how you answer the questions, such as in my case. Even if I wrote "I'm cured. You can turn off my disability now," they can't do that because they have guidelines that make you auto-qualify, and if your medical records still show that you meet those guidelines they can't legally shut it off.