Why has Metta made my friend hyper-sensitive to others' emotions and moody?

My friend has never been insensitive, but after beginning with Metta, she has grown highly susceptible to the emotional conditions of other people which results in terrible mood swings. When she is told bad news about a stranger she cries. Her partner fears that the practice is overwhelming her emotional system and is deteriorating the required boundaries. Is there a grounding technique that she ought to be employing to deal with this hyper-empathy and anxiety? Her DOB is 3rd March 1991. Time: 10:00 AM. Location: Kochi. My name is Arjun, and I am asking for my friend.