TDUI benefits

Question:

I have been Total and Permanent from day one of the IU, back in 1998. A few years later I felt better and wanted to use my GI Bill, thus I went on to obtain a BS, MS and finally became MD. Only once I remember that VA sent me a form to fill out about employment. Since it has been 20 years, can I have gainful employment now?  I have worked off and on for a few months without ever going over the poverty line in terms of earnings. It has been 20 years since I was declared 100% TDIU, Could I go back to work now and perhaps make a living without it affecting my 100%? Thank you for your response

Jim's Reply:

No. If you are capable of gainful employment, you aren't eligible for an unemployable benefit.