his mother. i guess
亲爸爸？

This article should answer your question.

http://www.cnelder.com/2006/7-17/11521.shtml

在电影、戏剧和电视剧里，光绪皇帝对慈禧太后以“亲爸爸”相称，是实有所本。那拉氏于１８６１年通过“辛酉政变”开始了臭名昭著的垂帘听政，一直居于“太上皇”的地位。在中国封建历史上，太上皇的高位，只有皇帝的父亲才能享用。慈禧既然自居太上皇，便喜欢皇帝以男子的称呼来叫她，以显示自己高贵尊威，这当然没有比皇帝叫她“爸爸”更为合适的了。

另外，光绪皇帝不是那拉氏所生，却在“爸爸”之前加个“亲”字，这是因为光绪的母亲是慈禧的亲妹妹。慈禧曾经说过：“光绪皇帝的父亲就是醇亲王。他的母亲，是我的妹妹。我妹妹的儿子，就跟我亲生的一样。”摘自《家庭保健报》）

hmm.. i knew it was something to do with the patriarchal society of imperial china.. i didn't know that the king's biological mother is actually the empress' younger sister tho..

Correct me if I'm wrong, was Cixi the one who also proclaimed herself as Lou Fat Ye?

Yes. You are right. It was Cixi who proclained herself as Lou Fat Ye.

yeah its so weird calling his mother " father" ! its really weird and annoying.

Well, actually, the term "Lo Fat Ye" was used even in generations before Cixi. I believe this is how a Qing Emperor's mother was greeted by her grandchildren.

lou fat ye is old buddha rite??

issit all emperor mum i called tat?

or juz the powerful one proclaimed themself to be..

Yes, Cixi was not the only one who used the term 'Lo Fat Ye'. But it was not a greeting used by Emperor's mother's grandchildren to greet her. It was a term use for the Qing Emperors. Because Cixi practically ruled the country during her 'reign behind curtain', people called her 'Lo Fat Ye'. So, she was the only Emperor's mother who was called 'Lo Fat Ye'.

Reference: http://gb.chinabroadcast.cn/9223/2006/09/18/1266@1222755.htm

The complex behind a simple name. *Sigh* haha. yeah, i'm a bit confused on that issue so..

i'm not too sure also...but from my rather poor historical knowledge her actual son who was e king died cuz of some STD. to maintain her power, she forced her nephew to become e king.