What? No he isn't. They are two VERY different characters.Cilan is just a copy of Brock (who admittedly wasn't the best of characters).
Brock: Womanizing breeder and ex-gym leader who comes from a large family.
Cilan: Pokemon connoisseur and gym leader who has many interests whose only known family is two brothers.
The only things these two have in common are that they can cook and are gym leaders. There are lots of gym leaders and I'm sure lots of people can cook. This does not make Cilan a copy of Brock.