Thanks for your query,based on the facts that you have posted it appears that your has multiple brown spots over his pubic region,
Most likely these are what is called as Fordyce Spots
The skin in pubic region is rich in sebaceous glands and hence prone to get more sebaceous cyst
due to accumulation of sebum beneath the skin.
Normally they fade away without treatment however they need to be treated if increase in size or get infected..
Observe proper personal hygiene by cleaning the entire area with warm water twice daily.