[anujkk]

Here is what I will suggest :

1. CSS Preprocessing Language : Any one of LESS or SASS.

2. Twitter Bootstrap or Zurb Foundation.

3. Concepts of UI/UX Design.

4. Let him do some projects and hone his skills. How about making his own website/portfolio or making some HTML templates/themes and try selling it on marketplaces like themeforest?

5. Once he becomes good at UI/UX Design & Development he can then focus on back-end. I would suggest him to go with Python & Flask. Learning Python language will not only help him in web application development but it will also allow him to explore & play other interesting stuff like Machine Learning, Computer Vision, etc.