Hi there
I am so sorry to read of your Dad's progression, Having an SCC is a very traumatic experience. There is no point in me asking retrospective questions, what has happened and where you and your Dad are now is all that matters.
If your Dad's cancer is under reasonable control with the treatment he is receiving the fact that he is now paralysed from the waist down should not preclude him from the same treatment as anyone else with full mobility.
You say he had already started chemo, depending on how well he is recovering from surgery and how physically strong he is that might just be able to recommence. As you say Abiraterone and Enzalutamide and other treatments may be viable later.
Is your Dad still in hospital? and is his regular Oncologist seeing him there You should try and be with your Dad at his next Oncology review so that you can ask all of yur questions. If he feels uncomfortable with you there then ask if you can see the Oncologist after your Dad as long as your Dad says he can share information then he should answer any questions you might have.
I am not sure how much help you have had from Occupational Therapy or others to give your Dad as much normality as is possible. There are so many things that can help physically, emotionally and even financially.
I will keep a tag on your post so that I can add more when you have had any further comments and maybe have posted a little more information yourself.
thinking of you
xx
Mo