It’s okay, I found something. But your document preferences has to have the units set to “points”.

// Number of columns in a table may vary depends on the book.
// If the columns count is constant then you can use the below script.
var myDoc = app.activeDocument;
var myWidths = [102, 420];
for(var T=0; T < myDoc.textFrames.length; T++){
for(var i=0; i < myDoc.textFrames[T].tables.length; i++){
for(var j=0; j < myWidths.length; j++){
myDoc.textFrames[T].tables[i].columns[j].width = myWidths[j];
}
}
}