There are medications that can help with arthritis pain. Your vet can help you with that.

Please read the thread on cataracts in this section. They are not a death sentence either. And fatty tumors are common in older dogs. My 13 year old has had several removed, the last one a year ago. Some are small and don't need to be removed. It depends on where they are.

Please talk to your vet. He/she can tell you the best course of action to take.