I don't think any public figure including bandmates should 'have to' make a statement and be criticised for not doing so. For all we know they could be expressing condolences and offering support to the family privately, which is far more meaningful.
Damned if they do and damned if they don't. If they were to post anything right now they would have people saying they are trying to make it all about them, if they don't post at all people say they don't care.
None of them have to post anything, they owe joe public no answers, no statements, nothing.
I'm sure the family/friends/bandmates/girlfriend will all have as you said expressed their condolences to one another privately.
Not everything has to be made public. these weird people commenting on family members', bandmates, girlfriends' posts demanding statements and answers really need to wise up a bit.