A few months ago, he started telling our mother to buy him more colourful clothes. All he ever wore was black and blue. He also started to criticise my mother's dressing.
He also started to be very active on WeChat. My mother realised that he was constantly chatting with this PRC lady. He said that this PRC lady was a friend of a friend. She "very poor thing", working overseas to support her daughter.
There are days when my father comes home looking happier than usual. Some days, he is grumpy. My mother looked thru his phone and realised that he always calls her before he reaches home and he texts her goodnight, with the rose and heart emoticons. Usually, when he is grumpy, it means that the lady didn't contact him.