Thanks for your question on HCM. Brain tumour are very notorious in presentation and also in response to treatment. They can rapidly grow in brain and compress the surrounding structures. They akso cause edema in the brain and cause high intracranial pressure (ICP) . Due to this blood supply of brain is hampered and patient looses consciousness and talks irrelevant. So your friend may had all above consequences. So immediately take him to the hospital. He needs urgent MRI to rule out brain edema and compression. He may need operation too, to decrease iCP.