melatonin, Gabba, 5HTP for children??

Hiya,

My husband wants to put my 11 year old daughter on anti anxiety medicine. I want to see if any supplements.She is already taking omega 3s, magnesium and vitamin D//K

1 . Has anyone tried Gabba supplements or 5HTP  or L-theanine for their ASD child's anxiety. Are they safe for an 11 year old in puberty?

2. Does slow release melatonin cause drowsiness in the morning?

3. Does melatonin cause feelings of depression and  misery in the morning?

Thank you for any comments.