There are reasons why disability attorneys shy away from claimants who insist on holding part time employment, the primary being that it in large part shreds most claimants credibility. RFC's are important, they are even more important if they are a reflection of the outcome of a two day professional functional capacity evaluation, nonetheless, these things do become predictable based upon age and skilled worker factors. ts been my experience that most claimants under fifty must establish an RFC of less then sedentary, as opposed to those over fifty establishing one of sedentary. This has a huge impact on the outcome of most hearing level decisions.

The op should contact an attorney and inquire of them if they are interested in taking his claim, informing them of "everything" including his apparent offer for publication of a work he wrote in just thirty days time.

I would be very interested to hear the outcome of that consultation.

Sounds like he mostly dictated the book and his wife typed it for him.
That assistance would factor in.. 30 days or not..
I don't think the 30 day book event will be a factor in the big picture.

example..
Famous artists may be able to knock out a wonderful painting in a few days, but the next one may take many months..

Technology already exists that would enable such an individual to work without any such aid from a second person.

Most new computers have voice recognition built in, so you don't have to buy nuance/ dragon software..
Some tablets and smart phones have a similar program I suppose.
I can dictate notes and messages on my smart phone.

I underwent training in Dragon more than a dozen years ago and even back then SS certainly thought it was a reasonable expectation that I could find work by utilizing just such an accommodation. (And had I not subsequently developed RSD/CRPS after the Voice Activation Software Programming training, I believe I could have made a living wage.)

An ethical attorney would confirm it must be disclosed. This is not a gray area.

Working PT can also show SS a pattern that the applicant did everything in their ability to continue working. It's really about the details of why they can't continue the PT work. For those that quit FT work and take PT work or work that allows greater accommodations such as working from home, sometimes they then reach a point where they realize it doesn't make "financial sense" to continue working, or they have a further decrease of function, or a combo of the two--and they don't realize they've been documenting that they their are capable of lesser work at the SGA level and undermining a potential SSDI application.

In this case, the work has already been done, it just hasn't been disclosed yet.

I agree it would be in his best interest to hire an attorney or a non-attorney rep for the hearing. One strategy the OP should discuss with any prospective counsel, IMO, is if during the hearing the book disclosure becomes a major sticking point and a denial seems imminent, to consider suggesting a closed period award. He can reapply for benefits later on if a career in writing is unsustainable. (OP you would want to verify your last date of eligibility for SSDI.)