Yes, but there’s a trade-off: the smaller the camera, the more limited the lens or sensor usually is.

A few categories to consider:

• mirrorless interchangeable-lens cameras (such as Micro Four Thirds or similar): these are smaller than DSLRs because they don’t use a mirror. With a pancake lens they can be quite compact and give near-DSLR image quality. But if you add a large zoom lens, the size advantage mostly disappears.
• bridge/ultrazoom cameras: these give you a big built-in zoom, but they usually use smaller sensors, which can mean lower image quality than larger-sensor cameras.
• advanced compacts: if she mainly wants manual control in a small body, these may be the best fit. Some compact models offer strong control over focus/exposure while staying much more pocketable than bridge or mirrorless cameras.

So the “best of both worlds” is possible only partly: you can get small size plus advanced controls, or small size plus some zoom, but a truly pocket-size camera with large sensor and long zoom is difficult.

Best advice: visit a camera shop and handle a few models with the kind of bag or pockets she normally uses.