Interest received from builder by surrendering flat

My Father, retired and income below taxable limit had invested in an apartment project upto 2014 and paid Rs. 22.10L... The builder went almost bankrupt and couldn't finish the project on time. My father called him up in January 2019 and decided to withdraw from the project and asked the builder to return the money with some interest... On April 2019 he called up and told me that he will return the money in few months and deposited Rs. 1L in bank account and went silent. Last December 2020 he assured my father he will return a total of Rs. 30L{including that 1L} and give a profit of Rs. 7.90L... And will pay in post dated cheque; instalments of Rs 5L from December 2020 upto May 2021...as of now 3 cheques have been cleared...

My question... will my father have to pay tax on the interest received by the builder... Since it is bufurcated into 3 FYs {1 lakh in april 2019} and rest in 20-21 and 21-22

if tax has to be paid, is there any way to save that hard earned money of my father (flat was not registered in my father's name since it wasn't completed.)


Can it somehow be treated as CAPITAL GAIN/LOSS (because in that case it is capital loss of Rs 10L- calculated using an app)


Thanx in adv and God bless