Dear aspirant hope you are doing well..

Yes of course your son can do data science course parallel with B. Sc course. Many IIT colleges offers data science course/ degree  from online .

The eminent educational institute, the Indian Institute of Technology or IIT, is offering several Data Science courses with a practical curriculum

• IIT Madras offers a three-level Online Degree programme. ...
• IIT Guwahati is offering ...
• The Department of Computer Science and Engineering of IIT Hyderabad is offering

Hope it's helpful thank you