Conversion To Islam
If the person asks for your advice then you can empathetically ask him to also look into Islam, offer him a copy of the Quran, and if he decides, point him to any religious scholars that you trust. However, if he’s not looking for an advice then your responsibility remains as it would be in the absence of this situation.
Thanks brother. May Allah give him hidayat (Aameen). And then the first cause would not matter as the outcome will be great.