Complex sentence: He decides that he can think of a way to save the town with the help of his best friends, Patrick Star and Sandy Cheeks, especially since Patrick is big and strong and Sandy is smart, but SpongeBob does not know what he can contribute.
Split into simpler sentences: He decides that he can think of a way to save the town with the help of his best friends, Patrick Star and Sandy Cheeks, especially since Patrick is big and strong and Sandy is smart. Sandy has smarts and Patrick has strength, but SpongeBob does not know what he can contribute.