Complex sentence: Varina Davis, who had taken another boat to Brierfield, met him on the river, and he finally received some medical care; two doctors came aboard further south and found he had acute bronchitis complicated by malaria.
Split into simpler sentences: Varina Davis, who had taken another boat to Brierfield, met him on the river. He finally received some medical care; two doctors came aboard further south and diagnosed acute bronchitis complicated by malaria.