In infants, hydroceles are fluid collections within the tunica vaginalis or processus vaginalis. During development, the testicles are enveloped by a double layer of peritoneum, which becomes the tunica vaginalis. With normal development, the processus vaginalis, which connects the tunica vaginalis with the peritoneum, becomes obliterated. If the process vaginalis persists, peritoneal fluid can track into the space surrounding the testicles, creating a communicating hydrocele. If bowel tracks down the same space, an indirect inguinal hernia is the result. If the processus vaginalis obliterates and traps fluid in the tunica vaginalis, a noncommunicating hydrocele is the result.
Surgical repair is reserved when the hydrocele is tense which may interfere with testicular circulation or large hydroceles that may cause discomfort. Communicating hydroceles in newborns should generally be observed. Spontaneous closure of the processus vaginalis and resolution of the hydrocele is common. However, hydroceles that persist beyond the first year of life as well as those that demonstrate changes in size (communicating hydroceles) should be operated because they are unlikely to resolve and pose a risk for development of incarcerated inguinal hernia.
hydrocele can be diagnosed by physical examination and transillumination of the scrotum ( it then demonstrates a cystic fluid collection.) Communicating hydroceles are often reducible whereby the noncommunicating hydroceles are not. for further investigation, a doppler ultrasonography may be used or necessary to rule out a primary cause.
Based on aforementioned, I would agree with the urologist or the general surgeon.
I hope that this information will be a benefit to you insha Allah,
wa salam aleikum