const cmCallBefore = 1;
      cmCallAfter = 2;
type
TProcedure = procedure of object;
TMyQuery = class(TQuery)
public
  procedure DoBeforeOpen; override;
end;

function Func(Obj:TObject; Mode: integer; inh: TProcedure): boolean;
begin
  if Mode = cmCallBefore then inh;
end;

procedure TMyQuery.DoBeforeOpen;
var X: TProcedure;
    c: TClass;
    M: TMethod;
begin
  TMethod(X).Code := @TQuery.DoBeforeOpen; // Статический адрес родителя
  TMethod(X).Data := Self;
  Func(Self, cmCallBefore, X);
end;

// test
procedure TForm1.FormClick(Sender: TObject);
var Q: TMyQuery;
begin
  Q := TMyQuery.Create(nil);
  Q.DoBeforeOpen;
  Q.Free;
end;