It's your father, in Petalburg city
Sure you can. In ruby, the third gym leader leaves his gym.
of course not
In the 8th gym. he is the gym leader
Winona.
Winona
The second gym is the Dewford Town Gym with Gym Leader Brawly.
8th gym leader
The 6th Gym Leader In Pokemon Ruby Destiny is in Down Pour City
The gym leader is not at the gym and that is why we cannot enter the gym.
simply go back to petalburg where your father is gym leader and you must challenge him
It is the Fortree Gym. Hope it helps!
Wassilij