Who take care of you, use whose 傳統...... unless she is being employed by you.
What do you think if 第日由your mother負責照顧坐月的起居飲食. buy your 99 希望your mother照your 99's傳統的方法來做..... what do you feel? To be fair, who do the work, who decided which 方法來做. The one who don't work for it, please close your mouth!
It's really depends on which method you like and suitable for you. If you think your 99's method is reasonable, then go with your 99 since it will make your c6 happier.