If s/he wants to grow in chess, s/he has to play it everyday, especially in the beginning. S/he can read books, or s/he can solve puzzles, but there is nothing that could replace playing. S/he applys what s/he learns to playing, and s/he gains experience from playing. S/he also learns lessons from her/his playing. How often s/he plays determines how fast s/he could progress, at least in the beginner stage. This is like any other sports.
Do you or does s/he care about win or lose? No, s/he should not. S/he gets experience by doing it. The more s/he does, the more familiar s/he becomes. Later, s/he would think about how to improve.
If s/he doesn't play, her/his knowledge is just on the book, not in her/his mind.
So, kindly nudge your child to play, everyday.