Diouly-dcp's answer
follow these steps
>open your firefox browser
>when the firefox pops up,,---click the firefox name located to your right (top-right corner of your browser)
>click option,,,-(even if you see other pop up menu just ignore and simply click option)
> you will see home page. and in the space available,, type the website you wish to set as home page and click okay.
to test it. restart your firefox.
you're done.
if after doing this your brother use it, when you come to the computer it does the same thing again,, it means that he change it back. that's all,
to avoid conflict you may need install your own browser and set your home page, such as (Google chrome) (opera) (internet explorer) ( torch) (safari). make your favorite. and set your home page.
you're done.!!