Your current approach will only render that/evaluate Model.IsAlert on the initial load of screen.
I would suggest removing the if statement, and defaulting this td to hidden, then change that depending on the properties in the model via a onChange event handler mapped to your checkbox control.
<td id="thingToHide" hidden="hidden">
@(Html.Kendo().Editor().Name("Explanation").HtmlAttributes(new { style = "display:show" }))
</td>
and some jquery code:
<script type="text/javascript">
$(document).ready(function () { // On page load method, check model and show textbox if needed
var model = @Html.Raw(Json.Encode(Model)); // get model example is taken from http://stackoverflow.com/questions/16361364/accessing-mvcs-model-property-from-javascript
if (model.IsAlert) { // If model IsAlert is true, show Explanation field
$("#thingToHide").show();
}
});
$("#YourCheckBoxId").on("change", function() {
$("#thingToHide").toggle();
});
</script>
Good luck Radha!