I would advise you to ask your son only , what he want to become in life. What kind of work he likes to do , as for we engineers we can get into any field of work . It should be your sons desire and passion about the jobs he would like to do . 

After B.TECH IN ECE , there are two  ways , either he can apply for further studies or get a job. 

For further studies, Masters in technlogy or MBA are both one of the best post graduate courses . Masters in technology will give him a job of a researcher( like a scientist) or a developer(who develops things like software ) . MBA will lead to a job in a private or government sector as a for example manager like General Manager , Operations manager, Marketing manager, Human Resource manager, Finance manager etc: 

Software courses are roughly of 19 types , he can be a master in any of the field . There are 19 types of developers in the information technology industry :

FRONT END DEVELOPER 

BACK END DEVELOPER

WEBSITE DEVELOPER

FULL STACK DEVELOPER 

MIDDLE - TIER DEVELOPER 

DESKTOP DEVELOPER

GAME DEVELOPER

GRAPHICS DEVELOPER 

MOBILE DEVELOPER 

DATA SCIENTIST 

BIG DATA DEVELOPER 

DEVOPS DEVELOPER 

CRM DEVELOPER

SOFTWARE DEVELOPMENT ENGINEER

WORDPRESS DEVELOPER 

SECURITY DEVELOPER

HIGH LEVEL DEVELOPER 

EMBEDDED DEVELOPER 

These 19 types of software courses are available everywhere , online or in any private institution . If he wants to become a software developer then he should be a master in one of the above courses shall lead him to a good job with heavy salary.