Complex sentence: Joe is then sent to the Philippines to destroy a bridge, he also met his brother Donnie, but he was unable to escape because his tank was overwhelmed by Japanese troops, forcing Joe to leave without him.
Split into simpler sentences: Joe is then sent to the Philippines to destroy a bridge, and he meets his brother Donnie. Donnie is unable to escape the islands because his tank was overwhelmed by Japanese troops, forcing Joe to leave without him.