It is difficult to tell with certainty (based on the picture provided) what the white patch in your son's ear canal is. Common causes of such appearance in the ear canal include:
1. Earwax (this may not cause any symptoms or can cause some ear blockage/itching when impacted)
2. Foreign body in the ear (Do ask your son if he has inserted anything in his ear)
3. Ear infection - Bacterial ear infections usually will result in ear pain, discharge and hearing loss. Fungal ear infections may not cause pain but more likely to cause ear itchiness, discharge and hearing loss.
It's best to take your son to see a GP with the appropriate equipments to treat ear conditions or to an ENT Specialist for an assessment and treatment.
Hope this helps and all the best!
