(collective) elder sister and younger brother

Rare spelling of 兄弟 (“siblings”, literally “elder brother and younger brother”).

even if ...,...cannot

not ... at all

very, exceedingly, awfully / (before a negative form) not at all, at all, by no means

It would be good if~

good / close / intimate / relationship

good relationship / close / intimate / friendly / amicable / middle

relationship

a surname