I feel for your mom. I was on that combo for about 2 years so I know what it does to your skin. The problem isn't the Avastin; it's the Xeloda. It causes a condition called "hand-foot syndrome" (HFS), which is very painful. My hands and feet were red and swollen and even my toenails came off!
Some investigators have observed that taking vitamin B6 (200 mg) can help HFS so you might talk to her oncologist about that possibility. It seems to work for some people and not others. In the meantime, follow these guidelines:
Avoid long exposure to hot water such as washing dishes, baths, etc.
Don't wear dishwashing gloves since they will hold heat against your palms.
Avoid using garden tools or household tools such as screwdrivers (any situation where you are squeezing your hand).
Avoid using knives to chop food because of the pressure of holding the handle.
These are the things that helped me:
Placing the bottoms of my feet or the palms of my hands on an ice pack or a bag of frozen peas. Use it on and off 15 min at a time.
Using a heavy hand lotion such as Aveeno, Udder Cream, Bag Balm, Eucerin, etc.
Wearing shoes a half-size larger to accommodate my swollen feet and prevent rubbing. (Keen sandals worked great!)
Putting my feet up whenever and wherever possible.
That said, if it's horribly painful, I would talk to her oncologist about reducing the Xeloda, or even stopping it for a few weeks. Xeloda stays in the body for up to 6 weeks so that would provide some chemo while her hands/feet were recovering.
Give her a hug from me!
Juliej