You can get the parent cell from this event using ParentOfType:
var cell = ((TextBox)sender).ParentOfType<GridViewCell>();
and desired child using ChildrenOfType:
var otherElement = cell.ChildrenOfType<YourControlType>().FirstOrDefault();
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items.