What to do after completing ECE if not good in studies?

After completing ECE, there is lot of short term courses which can help your son get a good job, some of them are as follows:

• VLSI Design
• TCP/IP
• Internet Fundamentals
• B-ISDN & ATM Networks
• Principles of Communication
• Transmission Systems
• Data Communication Networking
• Wireless Communication
• Performance Engineering of Computer Networks
• Digital Transmission
• Integrated circuit design
• Embedded circuit design
• Short Term Course on CMOS DIGITAL IC DESIGN
Programming in Java
• Cryptography, Protocols and its Implementations
• Evolutionary Computing Techniques with Engineering Applications

You can do networking trainings from reputed companies or industrial trainings from telecom companies like BSNL/MTNL, as some short term courses.