Question about bone spurs and bone scan

Hello.  I'm sorry to intrude on this area of the board.  I do not have breast cancer but I am on here due to other breast issues.  This question is about my dad.  He doesn't have breast cancer either but I thought that you wonderful ladies may be able to help me understand something.

My dad (no cancer diagnosis yet but there is a suspicion) has been suffering with a literal pain in the a$$ for quite a few months now.  He first noticed the pain while shoveling snow during a February or March snowstorm.  He thought he had injured himself and gave it too many months in my opinion.  Earlier this month he finally allowed his primary to prescribe a lumbar sacral x-ray which only showed numerous bone spurs along almost every vertebrae that was in the x-ray.  It also showed mild scoliosis and signs of atherosclerosis (hardening of the arteries disease).  i'm 100% sure that there is no mass shown on the x-ray (read the report myself to help my dad understand it a bit better).  Thinking that it must be a herniated disc I told him he needed to get an MRI.  His primary told him to go to a chiropractor.  I told him to skip the chiropractor (thank god) and to get an orthopedic doctor to prescribe an MRI.  He had this done last week w/o contrast.  I'm going to assume it was a lumbar sacral MRI but I do not have the report to confirm this.  If it wasn't an LS MRI then it had to be just a sacral MRI.  He doesn't have the report either and since I cannot read MRIs I didn't look at the cd he was given with the images on it.

All I know is this:

-There is a mass somewhere that wasn't evident on the x-ray.  I do not know the size or where the lesion is.  He wasn't given a lot of information.  He was given an oncologist's card and told to have a CT guided biopsy which he will have done tomorrow.  He was told this only by his primary.

-The orthopedic doctor told him to get a bone scan.  The two doctors do not know each other and the orthopedic never mentioned this mass over the phone.  My dad said the orthopedic wanted to see him sooner but by dad had fallen in the tub before the MRI and cracked some ribs due to the weakness in his leg.  My concern (just knowing what I know about cancer and I know far too much due to my own condition) is the bone scan.  If it was just a biopsy I wouldn't be as concerned since many benign things can form.

If anyone can shed some light on bone mets and imaging studies, I'd appreciate your help.  I see the big picture of all of these things combined and I haven't told him why they are doing the bone scan since I'm not a doctor but I have a bad hunch.

-Besides lung (he's a risk...quit smoking over 10 years ago), breast, and prostate cancer (no idea how that could be missed since he sees his doctor for type 2 diabetes every 3 months so I'm assuming his doctor does a  PSA blood test since he did one on my husband for no reason) are there any other cancers that typically spread to the bone (colon?  He never had a colonoscopy but has passed his occult stool tests in the past)?

-I know bone scans are typically done to look for bone mets and arthritis.  Would the doctor do this test for anything else other than these two things before even getting a pathology report on my dad's mass?  The orthopedic wants this done because my dad said he said something about a bone formation.  I'm not sure if this is a lytic lesion or if this is for the bone spurs.

-Can bone spurs actually be mets?  I know that bone spurs are a sign of arthritis, especially when there are so many on the spine, but can mets be mistaken for spurs on an xray?  Can mets actually cause bone formation/growth instead of lytic lesions or bone destruction?

I'm fearing he is stage 4 of whatever this is.  I'm literally shaking with fear and I cannot talk to anyone about this because they will get freaked out, especially my mom.  My dad is cool about what's going.  I don't talk to my mom about this because she's hoping for a benign outcome but I know just from the desire to scan his bones that the doctor's are pretty sure it's cancer which would make him stage 4, incurable but possibly manageable.  I know what stage 4 means in breast cancer.  I also know that there is at least one stage 4 cancer, Hodgkins lymphoma, which is actually curable at stage 4.  Are there any others (looking for hope while I wait for his pathology which may actually take less than 24 hours)?  I'm especially worried that it's lung or prostate since those seem to be the more likely culprits in his case but I so hope that it's non-Hodgkins lymphoma since it can be very indolent.  Hypothetically, if he had stage 4 lung cancer, shouldn't he have had symptoms by now?  No cough.  No coughing up blood.  No chest problems.  Nothing typically associated with lung cancer.

If anyone can help of give me advice about what they know about bone spurs and doing a bone scan before an actual diagnosis, I'd be very appreciative.  Thank you so much.