well, i have 2 younger sis, which i call them as da-mei and
xiao-mei. i might not treat them as good as i shud, but i do love
them.
my da-mei though is married and moved out to stay wif her hubby, i
still keep in touch wif her regularly. i consider myself pretty
close wif her, where we discuss abt family matters together, giving
advices to each other, etc. i even seek her advices on "woman
medical problems" for the purpose of knowing my gf better 
my xiao-mei is mentally-challenged who is staying together wif me
and under my mom's care. becoz of her medical condition, i've to
take care of her as a big brother. she's very temperamental and can
get into temper very often, but i always try my best to show her my
patience and give her something to "hong" her, such as treats or
play cartoon vcds for her to watch, etc.