Brief Answer:
Nothing specific is there..Adding supplements helps in growth

Detailed Answer:
Hi

Thanks for asking on this platform

I can understand your concern and this is very common to have this kind of questions in mind related to growth and development.
I won't get worried if child is growing normally ( weight and height for age) and there is no significant behavioral issues. Not remembering exactly what we supposed to does not means any nutrient, mineral deficiency or mental health disorder. You can consult pediatric neurologist for proper assessment if you are really worried. Or else I suggest you to supplement all kind of nutrients like protein, minerals, vitamins, omega 3 fatty acids in his diet either in form of foods like paneer, pulses, soyabean, vegetables, eggs if non vegetarian and nuts like walnut, almonds etc. If he is fussy eater you can give supplements like pediasure and multivitamin like zincovit . Also we need not to be very harsh saying disturbing words while teaching, always use words of positive enforcements.
I conclude that you need not to worry unless this issue is really serious. Give good diet or supplement. Monitor growth and do visit pediatric neurologist if you think so.

I hope this helps.
Please let me know if need any further help.
Thanks n regards

---