If the banks are saying NO to you, it does not mean that you are unable to get a mortgage elsewhere. We have an array of alternative lenders who may consider lending you money. They are not banks, and they will consider riskier situations. Their qualification rules allow them to fund mortgages in situations where the banks are stepping out.
But these lenders still want to make sure you are able to pay off your mortgage. You should not expect them to not question your income or the sources of your down payment.
You must have at least 15 % of your own down payment in order to apply.