Oh yes, you can get a lot on 16gb. I have never run out of space... I always erase them when I unload them onto the computer, so I really haven't done more than 1,000 pictures at a time at most and maybe 20 minutes of video.. I always unload them same day, but I'm sure you can get much more. I haven't ever even came close to half of the 16gb at a time.
No extra battery. Don't need it.. The battery charges so fast, and it last so long it's not necessary if you ask me.
Tell him just to fiddle around with the manual setting. I never read instructions, I am bad for that.. I just figure it out as I go.