Disabilities and Medical Conditions can be an important part of an AAC user's life as they can impact their daily lives so it's important to include their disabilities and medical conditions in their AACs, as well as anything related to them. People will ask questions and if the AAC user wants to explain about their challenges then they need the words to do so, but they also need the words to explain that they don't want to engage or don't want to explain for whatever reason they want. Remember that the AAC user is also a person like you and has the right to protest or refuse something, including discussing about their challenges with those they don't wish to engage or explain to, so they need the words to express that decission.
Don't forget to also include somewhere in the AAC somewhere that has comments about the challenges in question, as well as things related to the individual's challenges, like aids, challenges, needs, etc. Sometimes they want to have a conversation with folks, you need to give them the words to do so. This can include things like: 'do you like my wheelchair?', 'what do you think of how i decorated my crutches?', 'isn't my AAC cool?', 'can you help me decorate my walker?', and other such comments.
It's also important to make sure that the individual can explain about their challenges as there are many myths and stereotypes out there, especially around some conditions more than others, including AAC, and this can cause a lot of harm, pain, and frustration in the individual and can open them up and make them more prone to discrimination and abuse due to peoples' misconceptions. The AAC user needs the words to explain about their conditions and challenges to help protect themselves and reduce the risk of such ill treatment.