When you ask for a special circumstances consideration, you lay out all of the financial concerns, with documentation, that you have related to the medical expenses.
WRT using home equity and the like…those are things that would happen in the future. Certainly they should be mentioned as part of your request, but since there hasn’t been a need for this yet…there would be no documentation that you used these items (home equity) for medical expenses. There absolutely are some instances where it’s likely that could happen…but there is no documentation or guarantee that it will.
Loss of income is something that you document.
Just get the information on the process, and include any issues with documentation that you feel would be relevant to your situation.
These are handled on a case by case basis.