My initial gut feeling on looking over the Inspiration Mars documents is that it's much less likely to happen. Instead of using existing rockets, the updated plan requires the SLS in 2017, and the initial SLS flight is scheduled for 2017. SLS is could easily have a schedule slip due to budget, management, or technical issues. The plan also requires commercial crew to be ready in 2017, and many of the Congressional interests on the space committees are hostile to that program. It requires an accelerated development of an SLS upper stage, a radically-redesigned Orion capsule for Earth return, and a Cygnus-based habitat that also represents big changes from the current system. It requires big changes in NASA's HSF plans, an influx of NASA funding to get many of these things done, a willingness by NASA to engage in such a partnership, changes to ISS plans to test parts of the system, and a big change in NASA's HSF risk posture. I could see one or two of these things happening, but that is too many for me to believe are possible.
To be honest, I didn't think the original Inspiration Mars mission was going to happen, either. However, I thought it was a really important contribution that Inspiration Mars is working on advances in ECLSS, an area that is underfunded at NASA because of government-wide budget pressures and the budgetary appetites of some big NASA programs. This is still the case. So my advise to Dennis Tito, (and given his excellent business and technical background I'm sure he's just been waiting for my advise on how to spend a big part of his fortune), is to not worry about a dash to implement the flashy mission. Ultimately it will be more important to lay the foundation for such missions in the future. Don't rely on NASA funding in these difficult budgetary times, but instead achieve what you can with what you have and the funding you can raise privately.
So if he is unalterably attached to using the 2017 Mars trajectory, try a much easier uncrewed flyby mission to Mars then. Perhaps such a mission could include a Mars atmosphere sample return capability. Perhaps it could demonstrate some of the technologies needed by the Inspiration Mars crewed flyby at some later date.
Alternately, focus on developing and testing in space the ECLSS capabilities that such a mission requires. That is a major step that is not otherwise being worked on to a sufficient degree. The technologies could be useful later regardless of whether they are used by private missions or NASA missions. They also would be useful for other destinations, not just the Mars flyby.
Another possibility would be to concentrate on implementing the Cygnus-based habitat module or some other habitat module. This could include the Inspiration Mars style ECLSS if he thinks he can also fund that, or a more traditional life support system. Both would be big, high profile advances that would be inspirational. They would also be useful for the ISS if tested there, useful to leverage the COTS cargo capabilities and make them more sustainable because of additional uses, and useful for a variety of possible exploration missions by government or private groups to various destinations. If it can support a long deep space mission, it likely could also be a basis for a sort of mini space station even in LEO with extra radiation protection. Another LEO space station is a key element that is currently missing (depending on Bigelow's future steps) in the current outlook for commercial crew. Government systems could also interact with such a habitat-based mini space station module. Of course the habitat module could be an essential part of an Inspiration Mars style mission in the future.
There are plenty of other worthy advances in space capabilities that Tito could support. So I would recommend that, should things not work out for the big Inspiration Mars mission, that Tito not throw up his hands and walk away, but instead pick a more achievable advance and work to make that happen.