Advice for adult children?

30 F, living at home with my 62 yr old parents. My mother works part time teaching school children, and my father was recently in a work accident, becoming disabled (spinal injury) We are unable to afford care giver full time, as I am on disability myself for my chronic illnesses, I can hardly leave be some days due to the extensive pain I experience (Lupus, Severe Endometriosis, and Epilepsy) Since I am home and need monitoring myself, I have had to be the one to look after my dad.
He was able to walk minimal, but used to walk to the kitchen with his walker, he has trouble feeling his feet due to the spinal nerve damage, but he was still mobile, independent, did things for himself.

Fast forward a month, and he is literally sitting all day doing nothing. No more trying to move. His feet have swollen so badly as he sits in one place all day. He was too lazy to even TRY to get up, so he has urinated on the sofa, despite him wearing diapers, he will not get up to change them. He gets up at NIGHT by himself, goes into the kitchen to sneak food (junk food) and he refuses to eat any healthy food I make my family and I, due it not being what HE wants at that given time.
After working all day, he made my mum drive 45 min to pickup his fav candy, manipulating her to believe it was his last day and he could feel he is dying. When in reality he just wanted the sweets. :(

He ignores everyones help, and constantly is playing the "poor me, everyone do everything for me" card now, only during the day whilst we are all awake. He has got diapers sores from sitting in wet diapers, he smells terrible bec he chooses not to shower, or even try! He refuses to TRY, to move, walk, etc. like he used to do a month ago. His condition didn't change in a month, and dr is confused WHY NOW he can't do anything for himself.
I have no choice but to find a job to help support my family, as my mums income isn't enough alone.

How can I help my dad actually choose to take care of himself again?

Advice for adult children?
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