HRA deduction for individual

My client is a salaried person who receives a HRA of ₹120000 per month, and he is covered under 10% surcharge criteria. He he lives in his own parents home. He used to pay HRA of 8000 pm just to not furnish PAN. His mother is home maker and just have a capital gains as her income. Can he just increase the HRA amount to around 40,000 pm and furnish the PAN of the parents and get the eligible deduction. What problem will he face if he furnishes this in his ITR?