can cheque be presented if bearer of cheque expired recently

Dear Sir, My father had given about 5Lacs to a person, may be 3 years ago. He also took two post dated cheques from him 1Lac each on His Name, and dated in Oct2015. My father expired in Sep2015. 1) Is it legal to present those cheques to the bank now? 2) if the cheques bounced back, can I take legal action against that person? or can he take action against me since cheques present in absense of my dad? The problem is that person saying he had given back the money to my dad which is not true, and has no evidence. But my father had given him cheq payments only. Please suggest.