No child should be stuck at low beginner level for more than several months. Either s/he is not learning much in his/her lessons, group or private, or s/he is getting incorrect guidance. Either way, s/he needs a fresh restart.
If s/he has done all his/her homework, practices diligently as instructed, but still no progress, then the coach's instructions may be wrong. Switching a coach is necessary.
If s/he doesn't like the coach, then of course say bye-bye with no hesitation. The rapport between the student and the coach is critical for the coaching to be effective.
If s/he doesn't do his/her homework, rarely play, and not show any interest, then re-direct his/her energy to other interesting activities. Chess can be put on back-burner. Life is full of interesting things.