expressionsphrase-choice
In the following dialogs are both "like" and "(it's) not like" used correctly in the answers?
If yes, do they both mean the same?
What is the difference if there is one?
A: She says she's going to help you with your work.
B: Like I need her
help!
…
A: She says she's going to help you with your work.
B: (It's) not like
I need her help!
Is it that "like" contains a bit of sarcasm but "it's not like" doesn't?
Not only is it acceptable, it is also used quite frequently. You can also use other phrases such as "May I help you?", "Do you need help?", or "Would you like some help?". However, "Can I help you?" is probably used more often than other forms.
See Google Ngram Viewer: Can I help you, May I help you, Do you need help, Would you like some help:
This question is more about social interaction than language use.
Think about how you'd express your "real sympathy" in your native language. There are socially accepted formulas in every language and every society and culture, but your "true feelings" are expressed more by the tone of voice and the body language that you use rather than the words (unless the words are obviously inappropriate for the occasion).
If someone else's mother's been hospitalized for an illness, That's too bad isn't the best expression. I'm really sorry to hear that plus, perhaps, I hope she'll recover quickly is much better. Stick to the formulaic if you can't come up with a spontaneously appropriate expression.
My son, a native speaker of Chinese, not really a native Anglophone, says too bad all the time. I find it annoying, but I think he learned it from me. I use it for stuff like having to work two weeks straight without any time off and other unpleasantries of everyday life, but never to express sympathy for sickness or death or anything else that's serious.
Although it's difficult to say "Too bad" without sounding sarcastic, it's possible. I wouldn't advise it, though, because it's too terse, too curt, to be sympathetic. "That's too bad" is a little better, but, depending on your tone of voice and body language, it can express sympathy, but it's not the best way to be taken seriously by someone who's grieving about a loss or an ill relative.
Best Answer
Yes, both are used correctly. In both cases the "like" could be replaced by "as if". Both are somewhat colloquial expressions and might not be used by every English speaker.
As you say, the first use is sarcastic, meaning "I really don't need any help from her," with the strong implication that, in fact, she would either be completely unhelpful or possibly that she would make things worse.
The second is much less sarcastic. It says instead, "I think I can do this without her help." The implication is that you feel someone has challenged your ability to do something and suggested that you might need help from someone. "No", you respond, "it's not like I need her help! I can do it myself."