There is guidance on fee waivers here: https://assets.publishing.service.gov.u ... __003_.pdf
As you are in receipt of one of the specified benefits in paragraph E-LTRP.3.3, you do not have to meet the minimum financial requirements and would instead be assessed based on adequate maintenance. Under these circumstances you would be eligible to apply for a fee waiver the required evidence for which is detailed in the guidance.
You might struggle a bit due to what the case worker might consider "intentional disposal of funds", which is outlined on page 20 of the guidance. However, it is possible that it would be assessed that there are "exceptional circumstances" in this case and it sounds like you have documentation to support this.
It is not possible to guess at how UKVI will interpret individual circumstances and the only way to find out is to apply and provide thorough evidence and documentation to support your case.
I'm just a guy on the Internet who immigrated to the UK. My opinions are based on my experience and interpretation of the immigration rules and should not be considered legal or immigration advice; your mileage may vary.