father married Canadian citizen, mother died what rights do I have as son

my father is being neglected and psychology abused I am currently on his bank accounts but his wife wants me off wife was in nursing home and returned step sister was on accounts opened new with his funds trying to protect him. his mind is slipping and so is hers she feels he deserves nothing, not even to be taken care of health wise He has become her butler instead of husband and is not capable of doing it anymore. She is in wheel chair for last 6 years. Got him Vets money for his care and she said he doesn't need it, just wants money Paid for care myself and at present is still getting it but step daughter had medical care paper. They both badger him into signing papers. He asked me if he had to put her name back on it and I said no, but he has to live with results since I am in TN. he needed to see a doctor and finally after 3 months waiting I took him to emergency room St Anthony's I took him to see about blood pressure. No telling him how long he had it put him on meds not good si