Is it permissible to accompany old friends who do not pray and try to reform them?

Companionship has a great influence on an individual, and it is not permissible to sit with friends who do not pray unless the intention is to reform them and invite them to prayer. The reason for this is twofold: the obligation to denounce them for abandoning prayer, and the fact that sitting with them may weaken one's steadfastness, as the Prophet, peace and blessings be upon him, said: "The example of a good companion and a bad companion is like that of the seller of musk and the blower of the bellows."