My recommendation is for him to get the ST (Speech Therapy) and time will tell if he will regain this back. You have no control over this unfortunately.
I wouldn't be listening to whoever is telling you that "speech therapy can't help" because I can tell you they are incorrect. Yes, it is true that he might never regain his ability to speak even after ST, but that remains to be seen.
You will have to be patient with all this. There is NO quick fix to this. WORK with the ST too and get her/his recommendations as to what exactly you can do with him.
Never heard of any speech "suddenly" returning after going through this. Doubt that.
yes he has been ordered speech therapy and physiotherapy as well. But everybody around me saying that a speech therapy can't help it. It can come back just suddenly, there is no specific and really helpfull treatment for it. thats why i am asking here that what should i do.? i don't have any idea about it. But i will try my level best to recover his speaking power. so please help me if possible. thanks.
So sorry about your situation. I can imagine this being extremely upsetting.
Has he been ordered Speech Therapy at all?