Complex sentence: Maj Hagman was diagnosed with Alzheimer's disease in 2008, and Hagman at first took the lead in caring for her, but her condition deteriorated, and by 2010, she required 24-hour nursing care.
Split into simpler sentences: Maj Hagman was diagnosed with Alzheimer's disease in 2008, and Hagman at first took the lead in caring for her, but her condition deteriorated. By 2010, she required 24-hour nursing care.