1. They can apply together.
2. Given the info you provided you need a good reason for your mum's case for further extension. Maybe just apply for 3 months for your dad and your mum is with him.
Good luck!
2. Given the info you provided you need a good reason for your mum's case for further extension. Maybe just apply for 3 months for your dad and your mum is with him.
Good luck!