How to sort WinForms DataGrid (SfDataGrid) based on the number of items in the groups?

public Form1()
{
    InitializeComponent();
    sfDataGrid1.DataSource = new OrderInfoCollection().OrdersListDetails;
 
    foreach (var column in this.sfDataGrid1.Columns)
        this.sfDataGrid1.SortComparers.Add(new Syncfusion.Data.SortComparer() { Comparer = new CustomComparer(column.MappingName, this.sfDataGrid1), PropertyName = column.MappingName });
}
 
 
public class CustomComparer : IComparer<object>, ISortDirection
{
    string ColumnName { get; set; }
 
    SfDataGrid DataGrid { get; set; }
    public CustomComparer(string columnName, SfDataGrid dataGrid)
    {
        this.ColumnName = columnName;
        this.DataGrid = dataGrid;
    }
    public int Compare(object x, object y)
    {
        if (x.GetType() == typeof(OrderInfo))
        {
            var valueX = this.DataGrid.View.GetPropertyAccessProvider().GetValue(x, ColumnName);
            var valueY = this.DataGrid.View.GetPropertyAccessProvider().GetValue(y, ColumnName);
            if (valueX is string && valueY is string)
            {
                if (valueX.ToString().CompareTo(valueY.ToString()) > 0)
                    return SortDirection == ListSortDirection.Ascending ? 1 : -1;
 
                else if (valueX.ToString().CompareTo(valueY.ToString()) == -1)
                    return SortDirection == ListSortDirection.Ascending ? -1 : 1;
                else
                    return 0;
            }
            else if(valueX is DateTime && valueY is DateTime)
            {
                if ((DateTime.Parse(valueX.ToString())).CompareTo(DateTime.Parse(valueY.ToString())) > 0)
                    return SortDirection == ListSortDirection.Ascending ? 1 : -1;
 
                else if ((DateTime.Parse(valueX.ToString())).CompareTo(DateTime.Parse(valueY.ToString())) == -1)
                    return SortDirection == ListSortDirection.Ascending ? -1 : 1;
                else
                    return 0;
            }
            else
            {
                if (double.Parse(valueX.ToString()) < double.Parse(valueY.ToString()))
                    return SortDirection == ListSortDirection.Ascending ? 1 : -1;
 
                else if (double.Parse(valueX.ToString()) > double.Parse(valueY.ToString()))
                    return SortDirection == ListSortDirection.Ascending ? -1 : 1;
                else
                    return 0;
            }
        }
 
        //While sorting groups
        else if (x.GetType() == typeof(Group))
        {                     
            var countX = ((Group)x).ItemsCount;
            var countY = ((Group)y).ItemsCount;
 
            if (countX < countY)
                return SortDirection == ListSortDirection.Ascending ? 1 : -1;
 
            else if (countX > countY)
                return SortDirection == ListSortDirection.Ascending ? -1 : 1;
 
            else
                return 0;
        }
        else
            return 0;
    }
 
    private ListSortDirection _SortDirection;
 
    /// <summary>
    /// Gets or sets the property that denotes the sort direction.
    /// </summary>
    /// <remarks>
    /// SortDirection gets updated only when sorting the groups. For other cases, SortDirection is always ascending.
    /// </remarks>
    public ListSortDirection SortDirection
    {
        get { return _SortDirection; }
        set { _SortDirection = value; }
    }
}