His mother and father were locked in a bitter divorce battle, and each was demanding total loyalty and commitment from the child. Emotional abuse can be active. I'm ashamed you're my son. It also can be passive, the emotional equivalent of child neglect a sin of omission, true, but one no less destructive. And it may be a combination of the two, which increases the negative effects geometrically.
Emotional abuse can be verbal or behavioral, active or passive, frequent or occasional.
Regardless, it is often as painful as physical assault. And, with rare exceptions, the pain lasts much longer. The other children are quick to imitate their parents. Instead of learning the qualities every child will need as an adult empathy, nurturing and protectiveness they learn the viciousness of a pecking order. And so the cycle continues.