it might be something wrong with either the internet provider, the computer, the router, or the modem.
when i say router i mean that it could be loosing connection to the computer becuase the signal is not strong enough, not that the router doesnt support online gaming b/c online is being online wether playing or surfing.
is it only happening to to his comp? does he have good signal? has this been going on in the past or just started? have you tried restarting the router and modem? also does it loose connection then connects back right after or it just loosing connection and you have to wait a long time till it comes back?
i kno its a lot of questions but we need more info..