Hello and thanks for the query
I have read your query in detail. In my opinion your son needs another CT scan
of head and face to find out the cause of nose bleeding. ENT(ear, nose, throat) bleeding is a indication of Head injury
or internal injury of posterior nose. In addition to this the pupil are not of same size(?), which is also a indication of injury to internal part of brain. Speech altering and forgetting words may be due to some nerve injury
So you have enough reason to go for a repeat CT scan or even MRI
of head including Face, Hope this will clear picture and your son gets the treatment accordingly.