The second version is much stronger.Some thoughts:
1. You start with "Dr. Andrew Halifast prided himself as always being able to maintain his professionalism." The "as" throws me - should it be an "on"? I may just be crazy.
2. I agree with Anthony that you need to pick a name for the Doc - I assume "Drew" is your viewpoint character, so I would stick with it and drop the "Andrew" in the first sentence.
In "How to Write Science Fiction and Fantasy" OSC points out in his breakdown of the first sentence of Octavia Butler's Wild Seed that the name given to the POV character in the prose is the name the POV character uses to think of himself/herself. I understand you want the "formal effect" of the full name in line 1, but I think it's distracting.
Alternatively, he may think of himself as "Andrew" or "Dr. Halifast" while in the office, and "Drew" when he's not with a patient. That's a subtle shift in the POV, but could give powerful insight into the character if consistently done. Of course, I don't know if you have any scenes outside the office, or if that vehicle would even work.
3. "Lester’s had trouble accepting his wife wish of a separation." I think your 's is in the wrong place.
4. The first line of dialog from Lester is a good one. I recommend finishing it off with something visual. The response from Dr. Halifast, however, turns me off.
"Why would god wish a painful disease on your ex-wife? Would he not seek pity on her if she were unhappy with her life?"
The "Would he not" is leaning towards purple, and I can't imagine a shrink using it (not that I have much experience with shrinks), especially with someone with Lester, who instantly comes across as one of the duller knives in the drawer. (I also don't know what "seek pity on her" means") You're not going to succeed at making Drew come across as intellectual or philosophical by giving him arcane-sounding dialog.
My limited understanding of shrinks is that, when they get a response like that, they ask something more along the lines of "Why do you think god would do something like that, Lester?" (did you use lower case 'g' with Drew intentionally? It sets out certain expectations)
Dr. Halifax using Lester's name establishes something about their relationship tothe reader. If Lester then responds with: "She vowed to honor me, Dr. Halifax," then we get the other side of it. Just a thought.
5. "Lester Greensome proved that there were limits to even his deep well of patience." As innesjen noted, this does sound like the testing of the limits has already been done, when the rest of the first 13 suggest we're about to witness it. You might consider an alteration to something like "The depths of his well of patience were put to the test within minutes of Lester Greensome settling in on his couch."