Are you trying to help him out, or do you wish to stick to the requirement of the law? The interpretation depends on that.
1. If the notice period is of 2 months, then the employee has to work for the 2 months. If not, then he has to pay a notice salary for the period. In your case, he has worked 1 month and got salary for that 1 month. For the next month, if he is not working, he needs to pay 1 month's salary to you. (It's not just that he is allowing you to not pay him - he has to pay you.)
2. In recovering the amount due to him, you can adjust any other money due to him other than PF. Bonus, incentive, etc., can be adjusted for this purpose.
3. Is He Eligible for a Bonus?
If his salary is above 10,000 per month, then he is not eligible for a bonus. If it is below 10,000, then he is eligible for a bonus for the previous year (if not already paid) and for the number of months he has worked in the current year. Of course, you can pay the current year bonus next year when you pay for others. That is your choice.
I hope I cleared your doubt.
Of course, nothing prevents the company from giving a bonus where it is not due (ex gratia) or being lenient in settlement with an employee who they value and want to keep a good relationship. So if your management wants to help him, they can always pay or accept in settlement more than what the law says.