Help for 5 year after many remedies failed

My five year old has been treated by four homeopathic doctors since he was two. Some may have helped, but not a significant change. He is constantly whiny and unhappy, the next minute he can be very sweet. For his age is a little delayed in writing and remembering what he has been taught; takes many repetitions. Physically he is thin, fair, with big brown eyes. It’s a little confusing because he can be the sweetest child one minute and is very sensitive, and the next minute he can have a tantrum with yelling and sometimes hitting. He has a hard time paying attention, and comes by this prob bc as his mother I have add. He is scared of the dark, and does not want to sleep alone. He also has a fear of vacuums, he says that it will suck him up. He is very easily frustrated, and very much has to have the attention of his father or I. There are other constitutional traits I’m sure that I missing, but any help would be greatly appreciated as he has seen multiple homeopaths.