Hello I feel for you. Check with CAA and ask if they will give you a last chance sitting its possible and check dates, validity.
Its pleasing that you are thinking of your family. The airline world is difficult at the mom but may change. But what wont change is how much you will have to spend to get there. I am an examiner and have recently signed sep for ex cabair intergrated student he told me out of his course of 12 2009 all got through it all he is only one still flying all walked away to do something else. 80K poorer.
I think retaking the exams is possible but I would ask myself how much trouble it was first time round if it wasnt too stressful for you go for it again but if it caused you stress first time round wouldnt do it again lifes too short. Go to plan b and use your PPL and and gain FI rating, and develop present career, I still think you have to prove CPL knowledge to be paid for fi ing so what you have done to date may count but you will still have to pass nav. Speak to caa they can be helpful.
Instructing is fine run along side another job that pays bills, but your family is the most important part the equation especially in these difficult times.