In my experience, anyone can learn anything if given the right resources and guidance. I feel like I can help someone learn whatever they are needing help with. If it's a subject that I am unfamiliar with, I will learn it right along with them to help show that learning process from my point of view.
I find that using analogies, connections to personal experiences, and relating subjects to prior knowledge can help solidify those ideas that might need some polishing. However, there are many other strategies that help make something click and we'll find that strategy together!