This doesn’t completely answer my question though.
Zeldarocks: our prayers are with you as you complete your initiation!
Your RCIA instructor was certainly well intentioned in making this point, and I do applaud your curiousity.
The Catholic Church is incredibly diverse, yet many do not fully appreciate that fact. For example, I’m a Byzantine-Ruthenian Catholic. Loosely translated, that means I belong to a Catholic Church that follows the Byzantine Rite, evolving in Eastern Europe using a liturgical language now referred to as Old Church Slavonic (as opposed to Greek, the genesis language of the Byzantine Rite, originating in Constantinople). The faith was brought to that part of the world by Sts. Cyril and Methodius, brothers who are often referred to as Apostles to the Slavs, sent as missionaries by the Patriarch of Constantinople from where the Byzantine Rite originated.
As you can see from my example, it sometimes gets a little difficult to explain without some historical reference.
To attempt to answer your question specifically, I would guess your RCIA instructor was refering to the either the Coptic (Egypt) or Eritrean / Ge’ez (Ethiopia) Catholics. However, I’m puzzled because neither follow the Latin Rite in their worship, as your friend and instructor inferred. The both descend from the Church of Alexandria and have a unique Rite.
He could be referring to the Maronites, who descend from the Church of Antoich and do have a Western style of worship. It’s quite beautiful actually, and most Latin Rite Catholics adapt to it quite readily. It is however classified as an Eastern Rite.
Either way, you are now exposed to a bit of the full breadth of the Catholic Church, East and West!
P.S. There is a chart in circulation that outlines all of this. I would be glad to post it here if that would be helpful to you.