My difficult son is using his new baby to manipulate me | Dear Mariella

The arrival of your grandson won't sweep away old issues between you and your adult son, says Mariella Frostrup. It's these you must face

The dilemma My son, with whom I've had a very difficult relationship, recently had a baby. After a lovely and hopeful beginning where he seemed to be softening, he's returned to his old habits of saying and doing deeply hurtful things with every visit or text.

His son is my first grandchild and, of course, such a joy, but it's not possible to experience the happiness of the baby while receiving such abuse and hatred from him. He's said in the past that he behaves this way because of his mental illness, which I understand to be anxiety, but I find it is a very selective illness that comes out only at me.