The EstateCast episode discusses four important things that spouses should know before one of them dies. These include discussing dying wishes, keeping each other informed about important documents and financial accounts, sharing important contact information, and discussing preferences for burial or cremation. The episode also touches on the topic of remarriage after death and the importance of estate planning to ensure that the surviving spouse's wishes are honored. The overall message is that estate planning is an expression of love and care for one's family and should not be neglected.