Ummmm My younger daughter is in that position - husband walked out, it's all been horrible and it's still stressful now his girlfriend is making overtures to the kids. That's why I'm away on Mondays, I drive 60 miles to collect them from school, sort them out with homework etc., do extra work with spellings and tables and feed them until their mum gets back (she's doing a 'Teach First' course in maths so she can support herself and them) from next September. Since I can't drive at night (cataract forming) I have to sleep over, which leaves Mr J2 (86) on his own.
Yup, I understand about poverty and scrabbling to live - and working your socks off at the same time. Our income is also being hit by the petrol bills etc.. :(