How about a little more info? What would your brother consider to be important features?
size?
resolution?
low-light performance?
zoom range?
For general use, the Canon SD450 mentioned should be decent. As will most of the current offerings from Nikon, Olympus, and Casio.
As for Mac OS compatibility, iPhoto will detect the vast majority of current cameras. If it doesn't, a USB card reader will fix that.