He's arguing I won't cope
Ok. So his issue isn't with Home Ed per se. So show the judge all the ways you can cope. As user said, show evidence of the supportive HE community you are part of, demonstrate that you have a good support network. Show how you have been coping so far, use elder DC as example.
In what way were you not coping?
If relevant maybe a doctor's letter saying there are no longer issues, show evidence of the coping mechanisms you have used so that you now can cope. If relevant evidence that exDP does not have any evidence of your current ability to cope.