Complex sentence: He had lived mostly with his paternal aunts Shauna and Tammy Lussier, who arranged for most of his medical care; after the shootings, they expressed concern about the recent increase prescribed for his anti-depressant.
Split into simpler sentences: He had lived mostly with his paternal aunts Shauna and Tammy Lussier, who arranged for most of his medical care. After the shootings, they expressed concern about the recent increase prescribed for his anti-depressant.