Fire Control is a special rule in the Space Wolves Codex that states the Long Fangs may split their fire, not that they have Split Fire. There are a couple of key differences between these rules:
1. Split Fire requires a Leadership Test, Fire Control does not.
2. Fire Control can only be done if the Squad Leader is alive and does not shoot, Split Fire can be done as long as one model in the unit has that special rule.
3. Split Fire can only be done by 1 model in the unit, Fire Control can be done by any number of models in the unit; you just specify who is shooting at what before dice are rolled to hit.
In essence, the person your brother talked to at the Tournament was mistaken.