My mom has multiple conditions: arthritis, psoriasis, and pulmonary fibrosis are they related?

My mom also has spinal stenosis related to the arthritis. She gets epidurals and the doc there told her she has DJD, not RA. My grandmother had arthritis, but my niece has RA. What is the likelihood that my mom's conditions are all related? How do we know if she has psoriatic arthritis? Her psoriasis seems to be worsening along with her symptoms of the stenosis and also with the O2 she is on for the fibrosis (she was only diagnosed with pulmonary fibrosis a few months ago). She is going to see a rheumatologist on my advice. Do you think this is a wise move? Or will she only be wasting her time and money? I can't help but think that there is a possibility that something like Remicade or methotrexate might help her in some way. Thanks for your time!