Hi Henary ,
There are various way to earn from internet marketing various methods we have discussed over here in this forum also .
Now it totally depend on your brother qualification how he want to earn that
1) Doing Work ( Elance , fiverr , seoclerk , freelancer )
he can create a good and professional looking profile over these and sites and start making bids over the projects .
2) Passive income ( various methods IM is full of them )
he had to concentrate on 1 method study all methods for that avail on the internet either from google , youtube , udemy anywhere depend on the methods.
You need to invest also so that you create websites , social media presence and other things .
Amazon affiliate website.
Aliexpress , Ebay , Clickbank , Alibaba .
PPD ( pay per doownload)
PPI ( pay per install )
PPL ( pay per lead )
PPS ( pay per sale )
CPA ( Cost per action )
Some good networks
Google Adsense
Clixsense
Exoclick
Javbucks
Adultfriendfinder
Crakrevenue
Mylikes
Cpagrip
Cpalead
Revenyou
and many more ....