Gonna wait for the facts to pass judgement, but this doesn't look good. Doesn't look good for Greg. If this is a reoccurring thing, then Greg needs to go get some help and that girl is stupid for staying. Hate to see young brothas get in trouble like this, but if he commited the crime then he needs to take his punishment.
As for the topic on whether you should hit a female: nobody should be hitting nobody. If you don't want to get hit, then don't do any hitting. My pop taught me to never hit a female, but my mom taught me if anyone hits you to hit them back. It's all about respect. You hit someone, then your showing a lack of respect towards that person.