Dear SVA 2015, there's no need to worry. Let me tell you something very important in this era.
Some employers do not want an employee to join any other organization, especially competitors. For this purpose, they offer a plan called "Stay Period," which may last from 1 month up to several years after resignation from the organization.
However, in this case, the employer will pay you the full salary during your stay at home for a defined period, after which you can join any organization as per your will. During the stay period, the employer wants to make the knowledge and skills you acquired during employment with them obsolete.
During the stay period, you cannot work with a competitor or any organization doing the same type of business, and you will receive a full salary from the previous organization during this time. Nevertheless, you can join any other organization with a different type of business after obtaining written permission from the previous organization, but the stay salary will no longer be available to you.
In your case, as your friend's contract with the employer does not contain such a clause, there is no need to worry. The employer cannot take any action unless they have proof that you disclosed their business secrets to competitors.
Regards,
Ziad Hussain