Is it right for a nursing home to bill my father's medical and AARP insurance during the pending period for Medicaid?

this is billing for which the nursing home sent him to the hospital (due to a bladder infrections) to meet the 3 day period so when he came back they were able to bill at the Skilled Nursing rate; this happen three times. He was admitted 12-2009 very quickly at the nursing home when they saw he had AARP and Medical. Medicaid was denied in April 2010; at this time all charges had were billed and paid in full with the added Skiled Nursing fees by Medical and AARP. Then the Nursing home refiled for medicaid in April 2010, in June 2010 my father was approved with Medicaid who posted it could be retroactivated. The nursing home (eventhough they were paid in full with my fathers own insurances) went back and billed Medicaid form December 2009 as if they had not received a dime; then are now, asking us to pay the monthly retro from December 2009 as if they never were paid. Also, he was denied in April, why are they entitled to Start in December and not April 2010 when the second application was made? My concern is this, why should my family have to pay all of the retro monthly payments when my fathers insurance paid before he was orig. denied? And why would Medicaid be bill too? It looks like double dipping here? If I had not applied for medicaid I would not have to pay a dime for my father was in and out of the hosiptals during his medicaid applicatio so his insurances paid.

Also...the nursing home has ask us to sign a form H1200-A, they said it is a yearly recertification; but when I looked up the form it is a program transfer? Are they planing to transfer him out of his nursing home?

Please help, I thank you for your help.