Is prescribing psychiatric medicine to children is good or bad thing?

Depends. It really depends on the situation. Medications can be dramatically helpful for many conditions, when carefully prescribed by a trained child psychiatrist. On the other hand, there seems to be a trend towards over-prescribing of medications such as antipsychotics, stimulants, and antidepressants, sometimes off-label, and potentially with severe and unwarranted side effects.
Depends... Are they better off with medicine that they were before, or not? Good if better, bad if worse.
Child. In children please get 2nd or 3rd opinion, get psychological and neuropsychological testing done, meds must be used as a last resort and they can help with the right indication.