Not with AA, but generally speaking, yup! That said, are you sure that it's with American Airlines itself? A lot of stations (not all) have that kind of thing contracted out to other companies that do not receive flight benefits. As a rule of thumb, if the company doesn't own an airplane used for commercial service, the employee does not get benefits.

Oh, and siblings rarely get any kind of benefits. On UA, they get a slightly lower rate on the buddy passes, but that's about it.