Complex sentence: When Carl suffered a stroke in 1927, the family returned to San Diego; after he died in April of that year, Rosa remained there, living in Coronado, California, but was no longer scientifically active.
Split into simpler sentences: When Carl suffered a stroke in 1927, the family returned to San Diego. After Carl died in April of that year, Rosa remained living in Coronado, California, but was no longer scientifically active.