There is no such English word as "benefector".
However a "benefactor" is someone that gives aid/help/money/goods to another.
He did not himself undertake any voyages but was a great benefector and patron of the seamen who ventures dow the west African coasts to find a new route to the Indies. He also established the first school of navigation, where the sailors were taught navigation, cartography, and astronomy.
Yes, Magwitch is a benefactor to Pip in "Great Expectations." He is the mysterious benefactor who funds Pip's transformation from a blacksmith apprentice to a gentleman, although Pip initially believes it is Miss Havisham. Magwitch's generosity towards Pip is motivated by his gratitude for Pip's kindness towards him when he was a fugitive.