If she is a halfway decent teacher-- let's assume for the sake of discussion that she isn't quitting because she has decided she is lousy at it-- she herself is the best judge of her own learning style. Teaching her yourself is a bad idea in any case because you will almost certainly end up not speaking to each other :)
There are lots of possibilities and they aren't mutually exclusive: one-on-one, from a book, hands-on; follow instructions, figure it out yourself et cetera. Since you know computers and she knows how she learns, your job is simply to find the materials. And keep reminding yourself that the two of you may have different learning styles, so she may be doing stuff that you would never do.
Just keep multiple backups and don't let her touch your .htaccess file ;)