You are almost finished with a major project at work when a coworker from another department points out a problem with the original plans for the project. You agree that this is a problem, but in order to fix it you would have to go back and start over from the beginning. You don't want to do that, so you tell him:
At this point, I don't think there's much we can do about it.
"At this point" means "now". But you use "at this point" when it's too late or too early for something:
At this point the library is probably already closed. (too late)
A this point, all I know is that we're meeting some time on Saturday. (too early)
So when you use "at this point" it means "now" but also suggests that now is a bad time for whatever situation you're describing.
When someone is asking for help, but you can't help them (or don't want to help them), you use the phrase "there's nothing I can do".
Using this phrase makes it sound like you don't have any control over the decision to help or not help them. For example, if you are following a set of rules or if it's too late to make changes, you can say that "there's not much I can do about that".
(Print this lesson)