Where's my mom

I wrote down my mother's cell number wrong, and I couldn't get in touch with my father. I'm 2 hours late, and I have no idea where my mom is.
What am I to do? Turned on my super expensive roaming and called cousin Brian, but he didn't have my mother's cell. Good news is, he and his wife are expecting a baby.

Eventually mom found me, so now all of you know that the HK airport has arrival halls A&B. There is a screen that shows you both halls, but if you missed it, you're in for some confusion and roaming charges.