That appears to be a custom window, so you'd be looking for a window class that isn't in the default engine. And I'm guessing you're using a plugin for the layout since the default doesn't show HP/MP on the equip menu, so I'm not sure what the window name is that you'd need to draw it in.
If it's Yanfly's one though, it'll be _statusWindow.
If it's Yanfly's one though, it'll be _statusWindow.