Special situation, plz help.

I have 3 questions:- 1. How to calculate tax on arrears of pension recd lumsum and also got monthly pension too? 2. A house in the name of assesse has died and his son do rental agreement with tenent of that house and tenent directly deposit rent in son's bank a/c(but this was not written in rental agreement), then this rental income will be include in son's income or his widow mother income? 3. If after death of his father, his son gets interest (directly deposit at his bank a/c) on loan paid by father without any agreements and/or proof etc. to someone then this income of interest will be take as son's income bcz his bank statement showing Or his Widow mother's income. IN MY OPINION AS PER LAW AFTER DEATH OF FATHER HIS SPOUSE IS THE FIRST OWNER And THEN AFTER HIS SON, SO ALL ABOVE INCOME TO BE TREATED AS MOTHER'S INCOME AND SHE WILL LIABLE FOR TAX, NOT HIS SON AND DIRECT DEPOSITE IN SON'S BANK A/C SHOULD IGNORE. Am I right or not?? Also explain tax treatement of lumsum received arreare pension and thereafter monthly income continiously.