I teach three classes on beginning drawing and sketching to homeschooled studnets. In one of my classes I have one student's grandmother as well. While the lessons are geared towards kids, she has told me that she has learned so much from being in my class! I have seen this ladies work and she is fairly good already -- so the compliment was well taken.
Most adults need basic instruction, foundational items that we teach to kids as well with theonly difference being that the adult can grasp concepts and references faster. Meaning teach the same things but you can perhaps put two or more classes of information into one for adults. For my students at least, I purposely planned for them to draw all kinds of things regardless of what they 'like' to draw. Forcing them out of their comfort zone makes them a better artist for the area that they do like to concentrate on. If anyone wants a list of what I teach for the first semester, let me know. Have a blessed day!