Hello Welcome in H.C.M. I have gone through your query regardig treatment of deaf and dumb as your friend is suffering from this problem, his age is 25 years. According to clinical history of your friend it is clear that he had a congenital hearing loss therefore he can t learn the speech. Such patients can be treated but usually good results are directly related with age of patient. younger the age (2 - 5 years) ,results will be excillent. Any how now you consult ENT doctor for thorough examination and investigations to identify the congenital defect and finally if his acoustic nerve will be o.k. than COCHLEAR IMPLANT may be done followed by speech therapy. Probably above answers your query. Regards.