Old info, obviously, but that is the amount taken off an employer's NI bill https://www.gov.uk/claim-employment-allowance
So if your friend's bill has been, say £4800, she wouldn't have had to pay that because it would have been covered by the allowance. If she was worried about the increased rate taking it over £5000, then she doesn't have to be because the allowance has increased by far more to the point that if she was doing well enough to employ another staff member or increase hours for existing staff, she possibly could do so without incurring a NI bill.