PredniSONE and oesteoporosis

My dad had a leg amputation on Sunday. It could not be done at first because his blood pressure kept going up and down. Anyway he finally realized on Saturday that it was the prednizone making this happen. He has lupus. so i come online and find out about all these side effects. And he has most of them. He has been taking that stuff for over 25 years. He has the unexplained bleeding, the acid reflux, weight gain, blackened spots on his face, hardening of the arteries everything except the oesteoporosis thing. Now that he has lost his leg he will need to get the weight down so that he can move around comfortably. It is very depressing for me. he is 69. He also has a heart condition, i guess from hardened arteries and stuff, which was why they had to remove his leg. Anyway I can't seem to help feeling very helpless in this and i want to k now if there is anyway it is possible for him to get off this drug or even decrease the dosage. thanks for your responses.