Well, you only feel in the present, so he did feel things even though he may not have been who he used to be. We all are shifting and changing anyway, and our memories give us a sense of coherency, but the present is who we are most readily.

And, it can be terrifying to not know where you are or who you are for some people in those moments. So maybe he found some comfort in those moments with that one sister. That's how I think about it.