Deceiving in order to receive more money from a government fund

I live in Holland. A friend of us is cheating the social security with his mariagal status. The point is that a married couple will get about 1200 euros from the social security, but this friend did divorce on paper so that his wife could get a seperate social security of about 1000 and he himself about 900 euros. We have advised him several times that he should stop with this and change the situation how it should be i.e. registered as married and thus in case of need only 1 social security income. The person has also 2 children from his brother in Ghana on his name and thus was also getting money for them from the law. My question is, is it aloud to report him due the cheatings he is doing, so that they will stop him. He will have to pay back the money he received unjustly.