I can't help with the homeschooling questions. However, if a child has a sickness or disability that causes them to miss alot of school, they can NOT harass her or hold it against her in any way. If your child has a medical condition that is causing her to miss school, you should be talking with the school officials about an IEP or Section 504 plan. Please talk with your doctor and also look at wrightslaw.com for your child's rights. Then talk with the school counselor (usually the person who sets these types of meetings up). You can discuss the absences and the need for her to miss school because of her medical condition and/or disability and write that into the plan -- along with information about how to handle the missed work. I know children with cancer and other serious medical conditions or disabilities that cause them to miss alot of school (hospital stays, weakened immune system, severe anxiety, etc) and they have no problem at all staying up-to-date with their schoolwork even though they may miss ALOT of days.
Good luck.