You should use the View.Columns[someFieldName].Visible property to hide / show a column. Please also refer to the following topic:
http://documentation.devexpress.com/#WindowsForms/CustomDocument753
1. You don't need to create a GridView and assign it to the GridLookUpEdit as the View property. When you instantiate a GridLookUpEdit programmatically, it will automatically create a default View. The XtraGrid does the same thing.
2. You don't need to handle an event to set the column's visibility within the ShownEditor event UNLESS you want to decide at runtime to toggle the column's visibility. That is, for one row you may want to show Column A, and in another row you don't. If this isn't the case, you can set the visibility when you create the control.
3. Just set the Column's Caption proeprty for the "Dependent_Desc" field.
//Create a GridLookUpEdit repository item
DevExpress.XtraEditors.Repository.RepositoryItemGridLookUpEdit gridLookupEdit = new DevExpress.XtraEditors.Repository.RepositoryItemGridLookUpEdit();
gridLookupEdit.DisplayMember = "Name";
gridLookupEdit.ValueMember = "EmployeeID";
gridLookupEdit.DataSource = dtEmployees;
//Change the caption to a column
gridLookupEdit.View.Columns["Name"].Caption = "Manager Name";
//Hide the "Employee ID" column in GridLookUpEdit
gridLookupEdit.View.Columns["EmployeeID"].Visible = false;
//Assign it as the editor for a column
gridView2.Columns["ManagerID"].ColumnEdit = gridLookupEdit;