the part of brain which controls our speech has got damaged and so he is having aphasia
. The recovery takes place when the remaining part of brain takes over the function of the lost brain. It is a slow process and often frustrating for patient and the care givers. i would agree with your doctor that it may take another 3-4 months for improvement. Speech therapy
is the only option and there are no effective medication for recovery. You have to understand this fact and act accordingly.