Hi, 
I am Dr.Bruno.  I have read your question and understand your concerns. Let me try to help you 
Question 1 : What is the condition of Cerebral tonsilor ecstasies?
Answer 1 : It is actually Cerebellar Tonsillar Ectasia. This is a feature of a congenital condition called 
Chiari Malformation The symptoms (
dizziness , visual disturbances, ) you have described also fit in with this condition. 
Some 
numbness in his arms and hands, mean that there is a Syrinx Formation in his Cervical 
Spinal Cord Question 2 : How is this treated? 
Answer 2 : First we need to do a CT Brain to know whether there is hydrocephalous or not. If there is Hydrocephalous, we may have to do a Diversion Procedure 
Then, we need to do a procedure called Foramen Magnum Decompression for Chiari Malformation 
Hope you found the answer helpful.
If you need any clarification / have doubts / have additional questions / have follow up questions, then please do not hesitate in asking again. I will be happy to answer your questions.
Let me know if I can assist you further.
Take care.