I received a summons to appear tomorrow at the police station; but don’t be alarmed, it is obviously connected with my Dozentur. The government wants to know whether I haven’t some vile deed to confess that would render me unworthy of the noble title.
I am determined not to divulge a thing.
Freud to his fiancé,  August 12, 1885
Freud, Sigmund, The Letters of Sigmund Freud, (1960, p. 168).

One lengthy letter about the suicide of a friend [Nathan Weiss] reads like a memorable short story by a creative writer.
Roazen, Paul, Freud and his Followers, (1975, p. 49).

Thus, a French professor, and a psychoanalyst, Didier Anzieu, in his work, Freud's self-analysis, of 1986, stated that, in his letter,
Freud describes the suicide of a colleague, Nathan Weiss (1851-83), who hanged himself shortly after returning from his honeymoon, with a mixture of emotion, precision and intelligence, and goes on to offer an extremely subtle psychological analysis of the motives that lay behind his act (letter to Martha, September 16, 1883, L 73-80).
Anzieu apparently must have read a different letter to the one I have. True, Freud’s letter contains lots of emotions of a lunatic, but precision and intelligence are nowhere to be found. Bizarrely, Anzieu referred to Freud’s, extremely subtle psychological analysis of the motives for Nathan’s suicide. In fact, in his letter, often contradicting himself, like a fiction writer, Freud freely speculated about the motives of Nathan’s demise. Notably, as Anzieu explained,
Weiss seemed destined for a brilliant future as a neurologist; and his death, combined with Breuer's advice, convinced Freud to take his place in that speciality and to stay in Vienna in the hope of making a career there.
What a lucky turn of events. Just when Freud needed a position to be promoted to, the poor,  brilliant Nathan killed himself. Apparently, the fate itself intervened on Freud’s behalf, or vice versa. P.23
Or maybe Freud didn't need convincing, planning to take Weiss' place from the start, taking the fate into his own hands?
As a matter of fact, Anzieu’s speculations about Freud are no less bizarre than Freud’s about Weiss.
      Reading Freud insane rantings in the letter, it’s hard to believe that a psychologist, Sulloway, Frank J., Freud, in the Biologist of the Mind: Beyond the Psychoanalytic Legend, of 1992, proclaimed that,
Freud’s systematic and graphic analysis of the reasons for neurologist Nathan Weiss’s suicide in 1883 ranks as a masterful psychological study in its own right. (3)
Systematic? Masterful? Psychological study? Are we talking about the same letter?
I guess, at the time, unlike now, Freud was still, at least for some uncritical writers, the greatest thing under the sun, deserving unreserved adulation, no matter how bizarrely mad his writings and claims were.
        Also, Joseph Schwartz, yet another psychoanalyst in Cassandra's Daughter: A History of Psychoanalysis of 1999, claimed that, Freud’s analysis of the cause of Weiss’s suicide shows the same nuanced compassion that characterizes his psychoanalytic writing. (4)
Unless he was joking about nuanced, and compussion, he cannot have read the same Freud’s confused letter that I did. Moreover, there was never anything nuanced about either Freud, or his writings.
More recently, a professor of Modern Jewish Culture, Jay, Geller, in his, On Freud's Jewish Body of 2007, explained that, Nathan Weiss committed suicide at the start of … a brilliant career in neurology. ... Apparently both Freud and Breuer decided that Weiss’s death had created an opening … for a Jewish physician [aka Freud] to specialize in neurology. Freud would take Weiss’s place.(5)
One thing we can agree upon is that Weiss’s death had created an opening  for Freud so that, he would take Weiss' place. 
Remarkably, Geller didn’t find it remarkable that a young doctor, who had a brilliant carer, in front of him, committed suicide. And he is not surprised either that Weiss’ death, a lucky coincidence for sure, created an opportunity for Freud to take Weiss’ place. Or maybe it was more than a coincidence?
And, another psychoanalyst, Rita K. Teusch, in her review of, Courtship Letters of Freud and Martha Bernays, of 2017, added more fuel to the psychoanalytical Freud-worshipping pyre stating that,
When he reports the suicide of a colleague, Nathan Weiss, Freud’s reaction to his death and analysis of his personality are truly remarkable pieces of character analysis.
Sadly, as any non-psychoanalyst can verify, the pieces of Freud’s analysis are nothing more than rantings of an insane person in the middle of, as it appears, a cocaine-induced psychosis.
Also, one of the most recent Freud biographers, aka "critics", Frederic Crews, recounted that,
In September 1883 Nathan Weiss, a friend of Freud’s and an assistant to Scholz [in charge of the department of “nervous diseases”], hanged himself in despondency over the unraveling of his recent marriage.
Oddly, even though in other contexts pointing out that Freud was a compulsive liar, in this case, Crews apparently believed every word Freud wrote about the motives of the alleged suicide. Further, Crews explained that,
At the time of his death, Weiss was already a neurology Dozent in the University of Vienna— the very position to which Freud would be advanced in September 1885. (7)
No doubt, Weiss’ death was a wonderful opportunity for Freud to further his own career. How nice of Weiss - right when Freud needed a new position - go and hang himself.
(1) Jones, Ernest, Sigmund Freud: Life and Work: The Formative Years and the Great Discoveries, (1953, p. 166).
(3) Anzieu, Didier, Freud's self-analysis, (1986, p. 23).
(3) Sulloway, Frank J., Freud, the Biologist of the Mind: Beyond the Psychoanalytic Legend, (1992, p. 49),
(4) Schwartz, Joseph,  Cassandra's Daughter: A History of Psychoanalysis, (1999, pp. 60-61).
(5) Geller, Jay, On Freud's Jewish Body, (2007, pp. 90-91),
(6) Teusch, Rita, K., Courtship Letters of Freud and Martha Bernays, American Psychological Association, vol. 65, Issue 1, (2017, p. 339).
(7) Crews, Frederick, The Making of an Illusion, (2017, pp. 35-36).