。
He took pity on me and helped me out.
Literal
Me [object-を] pitiable [target-に] think-[and-て] help-give-[past-くれた-confirmation-さ].
哀れに思う ('to feel pity for') is the verbal form of 哀れ, using the adverbial に + 思う. Te-form chains to 助けてくれた (past of 助けてくれる). The final さ is a masculine/casual sentence-final particle asserting fact with a 'I'm telling you' feel — softer than よ but still emphatic. Casual recounting of a rescue.