here’s the link to ktr sukira where sungmin mentioned sis-in-law
wook: sungmin ssi…yesterday was ur b’day
wook: who gave you b’day wishes?
min: b’day wish? our members…and also kangsora sis in law
wook: she even gave you cake…kangsora ssi really…likes sungmin
min: kangsora ssi thank you, because of ur cake, my skin becomes better
cr: lovejc321 and scatterbrain (soompi)