I think, the game is up, the bubble has burst. Banks can no longer keep giving away loans to drive up demand (and consequently, the property prices), so 20 % is minimum so that they can cover their A$$e$ in the event of a foreclosure.
1. Your debt-to-income ratio is over 43%, but usually due to compensating factors you can go up to 45%. Debt-to-Income ratio has two percentages. The bottom percentage is the your future housing expense versus your combined household income which should be at 35% or less. The top ratio is the total debt which includes any car loans, credit cards, mortgage, taxes, insurance, etc. This ratio should be below 43%. If you truly can prove that you do not pay the mortgage at your parents house, then consider them as renters and complete a lease agreement. Then the loan officer, whomever it may be, can take 70% of the rental as income to add to your DTI ratio. Banks are a lot more stringent so provide good documentation and you should be approved. Let me know if this helps.