"If a dying 36-year-old mum wanting to take her boy on holiday for one last time isn't an exceptional case then I dread to think what is," she said today.
Stanton Middle School, in Milton Keynes, Buckinghamshire, has since apologised and performed a u-turn to allow Carlo, who has a 98 per cent attendance record, to have one final holiday with his dying mother after it was contacted by Milton Keynes Council.
A school spokesman said: "Although we knew she had health issues we did not realise the full extent of them. We should have checked further - we didn't, and we're very sorry.
"In the light of this we will of course grant this leave of absence, outside of normal school holiday time."
However, the mother-of-three, from Stantonbury, Milton Keynes, is still angry with the school after she was left terrified that she could be slapped with a fine.
"I had to fill in a form to give the reasons I wanted to take my son out of school during term time. I clearly stated that I had terminal cancer and this could be our last holiday together," she said.
"I just don't see how they could have made a mistake."
The law allows head teachers to grant leave of absence to pupils during term-time in "exceptional circumstances."
Under the guidelines, parents could be fined £60 for the unauthorised absence of a child, if it was paid within 28 days, rising to £120 if it was paid within 29 to 42 days.
Angela, who also has 13-year-old son and a daughter aged 18 years, tried to book an eight berth caravan at Haven in Great Yarmouth for a week in August.
Now unable to walk, the extra space was to accommodate friends to act as her carers.
"In August it cost £1,000, which I haven't got. So I booked the week from September 14, when it was £400 - all I could afford."
"Carlo has 98 per cent attendance, but this would have gone down as unauthorised absence. I was terrified I would be fined by the school."
