How do I override the disability amount?. Clicking on line 316 (S.1) & saying No, I don't have a disability makes me ineligible to deduct my medical expenses.

Deselecting the disability amount information does not indicate to CRA that you are no longer disabled. It's purely for the software's use. In order to claim the attendant care amount over $10,000, you must remove the disability amount. You're still eligible for the associated medical expenses.

How to remove disability amount and still NetFile?  If you override it in line 316 or in Form DTC, to set to 0, you can no longer Netfile.

There's no need to override the form itself. You only need to answer No to the qualifying questions to remove the credit from the return.