I'm an Arab, and I honestly would consider having a serious relationship with any girl from any race, ethnicity or nationality (Arab, Latina, black, white, Asian, Indian, American, British, German, Russian... You name it) as long as she matches these 4 conditions:
1. I'm attracted to her physically. 2. I like her personality 3. she is interested in me as much as I'm interested in her. 4. We both share the same religious beliefs.
This is just me, you won't here the same opinion from every Arab guy out there, but I could safely say that a Arab guys-Latina relationship doesn't seem that uncommon.
I see from your comments he is Lebanese from what I know Lebanon is probably one of the most western of arab countries so someone from there is probably the most likely to have an interracial or interfaith relationship.