overprocessed damaged hair

My grandma has really fine thin hair. My mom is a hairdresser and finally talked her into not coloring it anymore and just to let it go gray. It looks really good. In order for her to look like she has fuller hair she has it short and spiky. It makes her look younger and has a little bit of spunk with it.

Hello:  I'm hoping that someone can advise my mother about her hair.  She's colored it for years with home coloring products to cover the gray.  Now mom's hair is thin, dry, faded, awful!  Her hair has lost the ability to hold much pigment and shows white on the temples that the color won't hide.  My mom is really a pretty woman, and I'm thinking she would look great if she let her hair go silver (she's 73).  But the last thing she needs is any more color.  Apart from buying a wig, what should she do?