That's the whole point of word processing,
isn't it?
Frankly, at that early stage (and at this stage as well) none of us cared
whether or not Mom's letters had typos. We were more concerned with her
simply using the computer as a means of inputting information. We knew
that cosmetic changes could come later. We saw Mom's use of a computer
first and foremest as a means of maintaining contact with her children,
and since typewriters were never foreign to our family we had no reason
to fear that she might feel that the machine was getting between her and
us rather than facilitating that contact. Many people, former
neighbors included, find it highly impersonal to type letters. With
many of the handwritings that I've seen I've been caused to wonder in return
what's so personal about spending more time dechiphering a letter than
actually reading it.
The pen, typewriter and computer are, in the long run, tools for getting
thoughts and ideas onto paper (or into a usable digital format). As such
Mom's typing errors (they weren't spelling errors but rather mistakes that
occured while typing which she found it too complicated to try and go back
and change) were actually proof that she had a correct fundamental understanding
of what the computer was for. She knew that we'd go beyond the typing errors
in order to find the content (hey, after receiving it we could have even
sent the document to a spelling checker before reading it, and in that
way get an almost clean copy) so that's what she focused on.