There is very little EPA in the brain. The Omega-3 in the brain is almost exclusively DHA. That’s not to say the EPA is not necessary. The body can easily convert DHA to EPA as needed but the reverse conversion is much harder.
If you think of the body as a house, DHA is the foundation and walls (structure) whereas EPA is the water and electricity (functional) that keeps things running.
For a developing child, DHA is critical for healthy brain development. The purpose this product is to provide DHA in a tasty, chewable form if the child isn’t eating seafood two or three times a week.