I don't think that you are asking too much. And if you haven't already, you should tell him about your situation with your father so that he understands why it's so important to you. When i want to know if something was received, I always write, "Please confirm receipt of this email"

Also, even if you send him more than one email a week, I don't think that it's a big deal for him to respond to all of them. But, if you were sending him more than a couple of emails, then I think that you'd be a little unreasonable to expect him to respond to ALL of them.

Hope it gets better!