Welcome to HCM
Your father has suffered a Blockage most likely thrombus in Middle cerebral artery
because of which brain supplied by this becomes necrosed, because he must be a right hander so speech area is on left side so speech is also affected.
Because it is confirmed by MRI, what is the age of your father is he hypertensive or diabetic or smoker also High cholesterol
level.A check up of heart including Echocardiography
and a doppler study of both side of neck to see carotids.
These factor if any is present it must be taken care of.
Tratment seems to be OK.
One should consult a Neurologist
and you can discuss about antiplate therapy(Clopidigrel) and Citicoline
if they are required.
Another aspect is general care and physitherapy which is very important and once speech comes speech therapy