What's the Ruling of Living with Someone Who Doesn't Pray?

It is obligatory to advise, disapprove, and clarify to him that this is a great evil and that abandoning Ṣalāh is Kufr (major disbelief). So, if he was forced to eat with him without making him a companion and without becoming lenient in dealing with him. Rather, they end up gathering on one table or being invited without the intent of companionship, then there's no problem with that. However, he must not take him as a companion or become lenient with him. In fact, he abandons him. He should abandon him so that he repents to Allah. That's because abandoning ṣalāh is kufr as in the saying of the Prophet ﷺ "Between man and kufr (disbelief) and shirk (polytheism) is abandoning (Ṣalāh)." And the saying of the Prophet ﷺ, "The covenant that is between us and them is Ṣalāh, whoever abandons it has disbelieved." So it is obligatory to abandon him and denounce it (i.e., abandoning the salah). As for eating with him in a feast or eating together coincidentally, without taking him as a companion then there is no problem with that. The objection is that he shouldn't become lenient along with him.