。
Feeling sorry for them, she looked after the children.
Literal
She [topic-は] pitiful [adverbial-に] thinking those child-plural [of-の] care [object-を] saw.
かわいそう ('pitiful, poor thing') is the noun-form expression of sympathy or pity — frequently used as an exclamation (かわいそう!) when watching someone suffer. かわいそうに思う ('feel sorry for, find pitiful') uses the adverbial に + 思う ('think, feel') to describe the speaker's emotional response. 面倒を見る (literally 'see [someone's] hassle') is the standard idiom for 'take care of, look after,' covering everything from caring for children to nursing the elderly to managing pets. Notably, kawaisō (かわいそう) and kawaii (かわいい) sound nearly identical to learners' ears but are unrelated etymologically — か・わいい comes from older 顔映ゆし, and かわいそう from 顔映そう, both linked to faces but evolved separately.