Go to the search bar on Apun Ka Games and type "Family Guy: Back to the Multiverse."
Ensure Part 5 matches the size of the previous parts (usually around 500MB to 1GB depending on the host) to ensure it is the correct "piece" of the archive. Go to the search bar on Apun Ka
Scroll down to the bottom of the game's page. Most repack sites list all download links (Part 1 through Part 5 or more) in a single table or list. Go to the search bar on Apun Ka