Do you mean he earns less than £8000 in total per year despite the recent large increase in the National Minimum Wage from £10. 40 per hour to £11.44?
It's not clear in your post what his current earned income is because you write that he 'took a pay cut so is on less by £8000 a year'.
This gives an impression that his pay dipped by £8,000 so if that's the case, and he had a pay cut, it's not clear what it was previously and what it is now.
For example, was he earning £25,000 and it is now £17,000? Or he is actually earning less than £8k per year, i.e. £150 per week or £22 per day or £7.30 per day for each of you three?
If he is earning less than £8000 per annum, this means that out of a household with 3 adult members, only one of you is working and this 1 person is working a maximum of 2 days per week (at National Minimum Wage).
That would sound like a financial struggle, and particularly if there are more than 3 people in the household.
If you clarify the position, I'm sure the members on this forum will be able to advise how best to resolve this dilemma, such as how to challenge the decision or hardship resources.