Hopefully he finds it really simple, I got my psp phat when it first came out and had to wait for the 1.50 downgrade and those iso loader were awesome back in the day, but with DA and his CFW, the psp scene is so much different, it crazy how the scene has changed so much and how easy some stuff is compared to back in the day
this is an ok UMD dumper that I used back when I had a PSP.
If your memory card is too small, it will split the files for you.
If I recall, I had to rename the extensions from .000 .001 .002 etc. to .r00 .r01 .r02 etc. and use winRAR to extract the ISO inside.