The middle ear is normally filled with air, but in some children, this air is replaced by fluid. This is commonly known as Glue ear. Persistent glue can cause language delay, behavioural problems and erosion of small bones of hearing. One of the options of treating glue is grommet insertion. Mr Kumar can discuss if your child will benefit by having grommet surgery done.
https://www.nice.org.uk/guidance/cg60/chapter/Introduction
https://patient.info/health/glue-ear-leaflet