@Anna-Hertler Okay, then he may just need to register some horses on my profile, or use my money.
Just so he can have a stable outside the forum until he is old enough (If he still plays at that time
Mainsite accounts are only permitted to be used by one person- your brother is not old enough to take part in Equus yet, and that includes owning, buying and showing horses. When he turns 13 he is more than welcome to join us, but until then he can only play the Sims game and use our custom content (that you download for him.) We have age rules because people on our forum are allowed to use mature language and ideas. Locking now as this question has been thoroughly answered.
My horses may not be titled, but I can offer a breeding from one of my studs with my mare. My mainsite. Since my horses aren't titled I wouldn't ask for much in terms of the breeding fee, but you would have to register the foal.