Hello Harshu and thank you for writing to JustAsk!
Legible handwriting seems to be harder and harder to push in a child when the computer is being used daily within the classroom. Sometimes, students need to have someone they respect who is NOT their family member comment on their unreadable handwriting.
If you are truly concerned about his handwriting maybe ask your parents to talk with his teachers to see how his handwriting compares to others in his class. Also, there are lots of fun markers and pencils in the stores that are fun to use, help build writing skills and are not expensive. They may make a nice gift someday for him.