Is it Autism, ADD or ADHD?

Can someone help with perhaps addressing these differences for a general person. I have a family member that may have 1 of the 3 listed in the subject. The question is that it has never been medically diagnosed. The reason in simple terms is that the medical drugs associated with the treatments are not fully understood by the family members and there is a fear that this could more harm than good related to unintended side effects.

The young person involved is about 7 years old and is a gentle loving child with a beautiful spirit and is in general terms at peace but does show signs of hyperactivity [affects sleep as well issues related to staying focused. Other side of this is that the child demonstrates amazing aptitude for music and is very quick witted [ie. better than the average person].

Because of the fragile nature of the subject, how does one suggest treatment options for family members and how does one know if they suggesting reasonable and safe option?

Thank you.