In order to qualify to receive Social Security disability benefits, your disabling condition(s) have to prevent you from what the SSA calls
substantial gainful activity. Basically, you have to be disabled enough that keeping a full time job (or an equivalent time commitment, such as volunteering) is impossible for you.
I'm not a doctor or a lawyer, but the severity of Russhole's Moebius Syndrome doesn't appear to be severe enough to prevent him from performing substantial gainful activity. Certainly he has a few limitations on what kind of work he can perform (for example, since his inability to move his eyes without turning his head prevents him from getting a driver's license, he can't become a pizza delivery guy). However, there's still plenty of occupations he could perform with no limitation based on his disability. So that condition likely wouldn't qualify for disability.
Now, mental illnesses can definitely be considered disabling enough that they could prevent you from performing substantial gainful activity. However, any disabling condition(s) you want to put forward on your application for disability benefits needs to be backed up with evidence. That means you need doctors who will vouch for you being disabled so much you can't work, you need to be seeking treatment for your condition, and you'll have to provide medical records to the SSA. Since Strokey the Snowflake hasn't been treated for his bipolar disorder/PTSD/anxiety/whatever he's claiming today in years, and he stopped taking his medication a long time ago, he'd have a damned hard time proving his mental illness is severe enough to justify him receiving disability benefits.