Lainey: I asked the instructor about your question. She didn't seem to quite get what I was asking, but she did offer a good suggestion that you find out from the family if there are any special accommodations you need to be prepared for if you were going to take her out somewhere.
I've given the matter some thought and I think it would be important to be very clear about what assistance you are willing to provide. "I want to help" could be perceived as an offer to be another major care provider, whereas "I can offer respite assistance one day per week," or "I would like to take her out once a month for lunch and a movie" is much less ambiguous.