No problem,
I don't mean to confuse, but my understanding, from the implementations I've seen, is that SPF records (or lack thereof) are used to classify mail from a host, ip or domain as junk and "not accept" mail from the sender. (Perhaps the use of the term "junk mail" is too dated and interpreted differently by old dogs like myself
With that in my mind, my thought was that the issue may be related to an additional factor, since he stated that his mail was actually making it into his recipients junk email box.
Hopefully that clarifies my intention when I made my initial post.
Take care and I hope that you're problem gets resolved soon.
Best wishes,
Mike