It depends. I made far more than $1300 a month working till I was 70. Also, you have to consider two very important factors. First if you work till you're 70 vs retiring at 62, that is 8 years of retirement that you will not need to finance out of retirement savings and social security and that can be a lot of money. For example if you are single and your living cost in retirement will be about $50,000 a year and your S.S. is $15,000 a year then you will need to draw $35,000 a year from your savings or $280,000 over 8 years. Second, that additional 8 years of working allows for significant growth in your retirement nest egg, particularly if you have a 401K with matching employer contributions. However, the downside is loosing 8 of what would likely be the most healthy years in your retirement.
If your sister really hates her job that much and would be happier living off social security and whatever retirement she has been able to save, hopefully to last 30 or 40 years then she should seriously consider early retirement. I know a lot of people in retirement but only a few that live solely off their S.S. and seem to be happy.
For those nearing retirement age and needing to retire yet have not put away enough to retire are pretty well screwed. This is why I keeping telling my grandkids in their 20's that now is time start saving for retirement. Those early years are really important in building a retirement nest egg. Of course, they ignore me because they have other priorities.