It says her rent is £450, so the £600 is probably after her food shopping as she's probably got at least £2k pm coming in incl CB and top ups.
Which will cover the basics but also require careful budgeting to have a life too. So obviously will be a struggle if she is in debt or doesn’t budget for irregular costs like Christmas.
It says she's off work ill at the moment so maybe she's talking about her current situation while not earning.
There's not really enough information to know how bad she has it, obviously she's not well off but it looks like she's on the sort of money that some manage reasonably on but others will struggle because they live month to month rather than budgeting across the whole year.