difficult of learning and speaking

I have my little son boy and he is almost 5 years old and we notes that when he was in nursery he can't speak like the children in his age
We go to specialist doctor and he take some session for the speech difficulty but it was no improvement
We go to other doctor and notes that his tongue was tied from down and we make a surgery for untied his tongue.
After that he go to the school but still he can't engage with the student he always not concentrate and he can't save or memories his lesson still he have difficulty in the speech and pronouncing the letter and still he need so many session to be able improve and complete his treatment and also we need to make more consultation for him This type of treatment need a lot of time and time and effort so we need to try to cover the expenses of that as soon as possible cause it will be more difficulty when he grow up
I really appreciate you help cause as all of us know the children education it is very important and it is our future and support when we get old

thanks