What is the ruling on sitting with a fasiq (open sinner) when he is not committing a sin, without condemning him or reminding him of his sin?

It is permissible to sit with a disbeliever or an evildoer if they are not committing a reprehensible act. Allah has forbidden sitting with them while they are committing a reprehensible act, but has permitted it if they desist from it. Allah Almighty says: "And when you see those who engage in [blasphemous] discourse concerning Our verses, then turn away from them until they engage in another conversation." One is forbidden from sitting with an evildoer when they are committing a reprehensible act if it is possible to denounce them and there is no necessity. It is prescribed to shun them if doing so will deter them from their sin.