When I used healing ruby on an ally it only healed the master. I used <stpt> and I manually did it. The description says you can heal other allies and you can even target them, however you're unable to heal them as healing ruby just heal only heals you. I have also checked several different wiki histories up to 2006 and saw that the description has most of the time if not always, been heal target party member's HP.
http://ffxiclopedia.wikia.com/wiki/Heal ... did=169254
http://ffxi.gamerescape.com/w/index.php ... did=169254

There are many different websites that agree that it's for allies as well and I personally think it should be fixed.