غ produces a real /gh/ sound, distinct from /g/ (گ). It is a voiced velar fricative, a soft growl from the back of the throat. Native Pakistani speakers pronounce it correctly without thinking. Children writing in transliteration sometimes type 'gh' for both غ and گھ (which is گ + ہ); they are different. Encourage your child to feel the place in the mouth where each sound forms. Stroke timings approximate.

When she pronounces غسل with /gh/ from the back of the throat, that is muscle memory of two languages working together. Name it.