Baby H. pyloric stenosis

Hello,
i have a second identical twin baby nine weeks old that was vomitting but not too much, approximatly once daily but not the whole amount he eat, except two times he had sever vomitting with projectile, he is not dehydrated as well as he is making stool twice a day and normal urine.

i am feeding him every three hours in average of 100 ml milk, he eats good, but after finishing the meal he start making pressure on his belly as if he wants to make stool but he is not, i made for him ultrasound sonar and it results on that he is H pyloric with MT of 4mm and length 20mm. is it possible that this H pyloric be removed alone with time or it needs surgery for treatment????

thanks a lot for attention.

sincerely,
ebtisam nassif