... You write about ...
sheyichye [and his problem with epilepsy]:
In such instances, there are medications that not only ease [the severity of the seizures,] but also lengthen the interval between one [seizure] and another. Moreover, [the medication causes] the intervals [between seizures] to grow longer and longer.
Something here is puzzling, [as to why the problem is so severe,] since the doctor whom you mention in your letter is known as an expert in this field. Possibly you are not following his instructions, for which reason you have yet to see an improvement.
(Igros Kodesh, Vol. XVI, p. 181)
... In particular with regard to that which you write about your son ...
sheyichye [and his problem with epilepsy]:
I am somewhat astonished by what you write, since many new medications have been discovered of late for the treatment of epilepsy, may G-d protect us.
Although these medications take time [to become fully effective,] an improvement is seen almost from the outset, and with the passage of time the situation becomes better and better.
Consult again therefore with your specialist; he is surely aware of the doctors [who excel in this area] and of the new medications that have recently been developed and which your son should again try taking. ...
(Igros Kodesh, Vol. X, p. 367)