The most important thing is your Dad's health, and the frustration of the delay while your waiting for the test results will unavoidably magnify every other problem whilst the real big issue is that one. I remember being in a similar boat about 6 years ago when I thought my Mum might have breast cancer and it was in the middle of the divorce, Dad was playing really dirty over the finances etc, me and Mum faced a very uncertain future we didn't know if we'd have a house or not. Fortunately Mum was clear and everything else was manageable after that.
If your Dad gets redundancy then it changes the situation as regards what you are entitled to, especially as (given that you said you had a big mortgage) I am guessing you have had to pay fees as well? If you can't find anything on the Student Loans website then I would try the university that you are going to - they might know what to do in order to get your fee status re-assessed. If you find you're coming up against people passing you around etc ask to get in contact with the counselling department at the uni you're coming to, they will give you practical advice on it and they will treat you as a student already even though you haven't started yet.
What you are experiencing now is probably going to be one of the toughest times that you will find yourself in in your life, take the time you need for yourself and make sure you talk about it to someone, if the easiest way is to use this forum then thats good. Keep safe and stay in touch x