When do you transfer from Home Health Care to Hospice?

My 90 year old Father was sent directly home from the hospital 4 weeks ago. This was an insurance driven decision. He had a bleeding ulcer in June, had a two week hospital stay and was release to my brother and I to care for him at his home. Up until May of this year he lived completely independently, neither of us live full time with him or even close. Both of us have homes hour away from his home. Since hospital release we have been splitting time at his home maintaining care. He was set up with Home Health Care, which provided, nurse visits, PT, OT, and health care. These services are intended to help him become self sufficient. However, we are 4 weeks in and there has been no improvement. Actually he is worse now than he was at release. He refuses to leave his bed, refuses food, and has to be given water or he would not be drinking. When do we know that hospice is a better choice in care? Has anyone had personal care help that stayed for longer than 4-6 hours at a time? Need some advise. Thanks