Legally a last will and testament is to serve as a directive to transfer property (real and personal) that a person owns upon their death. Sometimes a testator may leave an item to a relative along with a mention of why. Sometimes a testator may indicate why a certain person was left no money or property in their will. The testator may mention a child and give them a token amount so that it is clear they were not left out. They may mention earlier amounts that were given or loaned to a specific heir and how those amounts are to be handled after the testator died.
But a will is not a list of the heirs that the testator loved and the ones that the testator hated. Do not draw that conclusion. A testator may have given property while still alive to Child A and continued to live on the remainder of his property until his death. That property he gives in his will to child B–simply because he wanted to live on it until he died.
A will is to direct the disposition of assets after someone dies. It’s does not have to be a list of heirs they loved.
Always remember that legal documents have legal purposes. Individuals may have personal reasons as to how those documents are constructed, but those reasons do not have to be stated and sometimes more than one set of unstated reasons can logically explain the way a will was set up.