Is it permissible to communicate with a male cousin via social media to encourage him to pray and draw closer to Allah?

The cousin [son of the paternal aunt or maternal aunt] is not a mahram for a woman, and it is not permissible for her to be unreserved in her conversation with him under the pretext of offering advice, because the Prophet, peace and blessings be upon him, said: "I have not left behind me any fitnah more harmful to men than women." It is more appropriate for men to advise him. The Muslim woman should keep away from situations of doubt, such as conversing with non-mahram men without a recognized need, and warding off corruption takes precedence over securing a benefit. The female Companions used to enjoin good and forbid evil within their own circles, and they did not pursue evil among men.