Most probably, since she has been the one visiting him while the latter is in remand. A very "filial" mommy I would say, taking orders from his teenage son.
When asked by reporters, she refused to answer. That was a giveaway.
If Tin Pei Ling can have administrator posting for her in facebook then, why not Amos Yee now? So there is no need for Amos's mother to answer the reporters' questions or any allegations. Did TPL announce who was her administrator then? If TPL no need to announce, Amos no need to announce or account to anybody too.