Is it zaayiz/permissible to meet with, come infront and to speak in mobile with the husband of sister? Again will it be permissible to come infront,to meet with or to speak in mobile in a low voice with the husband’s younger brother or brother-in-law?

Now-a-days people are not giving importance to this Masyala/rules. It is totally Haarwam and not zaayiz/permissible to come infront or to meet with or to speak in low voice in mobile with sister’s husband or sister-in-law. Similiarly it is also Haarwam and impermissible/not zaayiz to come infront or to meet with or to speak in low voice in mobile with husband elder or younger brother or brother-in-law. There is a Haadis Shareef that, “ Brother-in-law is comparable to death”.(Mishkat Shareef) So everybody should be concious regarding this matter.