Hmm. Joint pain could be lupusy but it depends how it presents? Symmetrical or not, which joints, swollen/red/hot, permanent or spasmodic? See if you can find out and post back.
It doesn't sound lupusy that he has done nothing about it. In my experience, doing nothing is not an option, as when it kicks in its impossible to manage... even going to the loo is something I have to do a lot of building up to :) having said that, autoimmune diseases are a bigger for presenting differently.
Hair loss also lupusy, but more in spots like alopecia rather than male pattern baldness.
Raynauds common to a few autoimmune conditions.
A blood test would be the starting point. If it is autoimmune, depending on what it is, organ involvement can be present, and potentially serious. Give his head a wobble and get him checked (that helpful titbit just in case you live on a parallel planet where men actually listen :/).
Autoimmune as pp said do tend to cluster in families. My dad has psoriasis and severe psoriatic arthritis, I have lupus.
Does he have any other symptoms?