You’ll need to use the figure of £132.66 for what needs to be remaining after rent and council tax due to his child. 
I don't believe that's correct.
1) As I understand it, you only need to include the child in the calculation if they will be living in the same household as the sponsor and applicant.
2) Also, the figure of £132.66 is a) out of date (it's the rate for 2015, not for 2017/2018) and b) it's for 2 children and no adults.
The current figures for 2017/2018 are:
- £114.85 per week for the couple
- £66.90 per week for each child living in the same household
So, if the child will be living with you, then you need to show at least £114.85 + £66.90 = £181.75 per week after rent and council tax
If the child does not live with you, then you only need to show £114.85 per week after rent and council tax.