A member just asked me the following "Looking for a class online for a client with NO core strength? I find that some middle aged women have very poor upper body strength. Can you advise please?" Please help with ideas.

Using the Magic Circle is especially helpful for those whose upper body is weak. And if your upper body (not just the arms, mind you, but shoulder girdle as well) is weak, your core will be, too. The MC works well in establishing the connections of upper body strength and core strength. Then layering in weight bearing on the arms, if the client can tolerate, is a good progression.
Of course, PA offers some nice classes targeting arms: 462, 192, 345, 189, 235, 151