Cheque bounce case - Sec 138

This is case of my son. My son took loan of Rs.1.5 lakh in April, 2020 from his friend. My son gave him two signed blank cheques. My son returned this loan in August 2020. His friend returned only one cheque and said the other is lost. In September 2020 my son took another loan from relative of that friend for Rs.2.00 lakh and signed one agreement and also gave one blank cheque whose number was mentioned in the said agreement i.e. Cheque No.738982. My son returned this loan also on 6th January 2021 by cheque and got back agreement and blank cheque. Sir, to our surprise, on 19th July , 2021 my son got a Notice from the said relative of his friend that my son had took loan of total: Rs.14.00 Lakhs, in cash from him in parts ( kai bar mein) for construction of his house and returned only Rs. 2 lakh and demanded Rs. 12 lakh. Actualy he got a cheque No. 738981 dishounred for Rs.12 lakh in July, 2021. I came to know that friend of my son gave his cheque, which he said was lost, to his relative. Relative of my son’s friend said in notice that this cheque was given to him in June, 2021 by my son. You will see that cheque Number mentioned in the notice of 19th July, 2021 is 738981 while cheque No. given in the Agreement of September, 2020 to that relative was 738982. This clearly shows that this is an old cheque prior to Sep. 2020 which is misused by the relative of my friend. Further my son has no house in his name. Pl advise defence we should take in this case. Also advise under which circumstances court can pass order to pay 20% interim compensation u/s 143a of N I Act after start of trial.