How do you make your parent understand that you are doing what you have to to help them, without them getting upset with you?

They will get upset, as they feel their independence is threatened. Please try to introduce help gradually, perhaps with the focus that they will then have more time to do what they please.

Try very hard to to appear you want to take over their lives. If things are at a critical stage, try to get a close family friend or a faith community leader they respect to talk with them. Third parties can often be a big help in bridging this gap. They take out the family dynamics in that "the kids don't think we can do anything and they want to boss us around."
Always keep in mind their dignity as best you can.

Good luck. I know it's hard. We've all been there. Please keep reading the forum and the articles. It will help.
Carol