You can get any personal information of third party under RTI as per Delhi High Court judgment. You have to argue your stand in the ongoing case. Filing IT complaint is a different issue. You may complain to the principal of that Medical college enclosing his statement and request him to inquire into the financial details of the class IV employee as his earnings and assets are disproportional and make this as copy to ACB.
Except this way of spoiling the relations, you are not going to achieve any thing. Focus on main issue and get out from the case first.
No one can take granted the knowledge of a judge and during case the parties will be coming out with such facts during cross examination.