"He looks out for opportunities to help others in need" can be replaced with “He looks for opportunities to help others in need.”

"He looks out for opportunities to help others in need Can I replace “looks out for” to looks for ? No. They are different. "Looking for" is a search. "Looking out for" is alertness. Here is an example to illustrate. Let's compare: (1) "When you are downtown, look out for pickpockets" (2) "When you are downtown, look for pickpockets" #1 is what you would normally say to a man in order to warn him to be careful of pickpockets. #2 is what the head of the police department would say to his officers: "Go into the city, look for pickpockets, and arrest them."

Yes, you can replace "looks out for" with "looks for" in this sentence. Both phrases convey the same meaning of actively seeking or searching for something.