I've been going through this for awhile. Talk with your vet, mine is awesome, and explain what is going on and that you want to develop a plan for your pup as he ages.
My older GSD is 13 years old, is a lean 100lbs, and is towards the end, here is his regiment. Take this in to your doc, none of these meds are overly expensive, which makes it an easy choice.
Carprofen- 75mg every 12 hrs. It provides day-to-day treatment for pain and inflammation from various kinds of joint pain. https://en.wikipedia.org/wiki/Carprofen
Gabapentin- 300mg every 12hrs. It is recommended as one of a number of first line medications for the treatment of neuropathic pain. If the hips and back are super bad, he is probably at the point of nerve pain. https://en.wikipedia.org/wiki/Gabapentin
Tramadol- 1-2 30mg tablets every 12hrs. Tramadol is a synethic opioid. Tramadol is used primarily to treat mild–severe pain, both acute and chronic. Tramadol is considered similar to morphine, and is probably not something you are going to be using all the time with your pup until he is near the end. https://en.wikipedia.org/wiki/Tramadol