Stating the obvious, dead branches in your tree can be a symptom of a serious problem, right.
To reduce the potential for long-term damage, the cause of branch dieback should be determined as soon as possible so corrective measures, if practical, can be implemented quickly.
Also, if dead and broken branches aren’t removed under controlled conditions, gravity will eventually exert its influence - damaging healthy branches on the way down, as well as anything on the ground beneath the tree (I hate when that happens)!