Referral fee received in addition to salary

Hi 

One of my CA friend who is an employee of non-CA firm engaging in Debt syndication is due to receive 8.90lakhs referral fee for introducing a client to his firm.

Query:

1. Is charging under salaries head compulsary as there is already an employer/emplyoee relationship with that same firm?
2. If not, can he claim certain expenses to reduce tax liability from 8.90L fees received?