I’m sure there’s something out there, but I don’t know what it is. I would encourage your friend to try it out as is. If they try to make Firefox look and feel like Chrome then they will inevitably just want Chrome back. Instead, if they try out things from the Firefox way of doing it they will actually see if they like it for what it truly is. At least, I’ve found the most success with browsers that way, let them shine for what they are and see which I like. Change is always hard, especially in something you use for hours on end every day, but maybe with your encouragement they will be open to it.