What does "collapsed about him" mean?

Context:

Waite, who authored an extensive psychohistory of Hitler,
concluded that he suffered from borderline personality
disorder, which manifested its symptoms in numerous ways
and would imply Hitler was in full control of himself and his
actions. Others have proposed Hitler may have been
schizophrenic[citation needed], based on claims that he was
hallucinating and delusional during his last year of life. Many
people believe that Hitler had a mental disorder and was not
schizophrenic nor bipolar, but rather met the criteria for both
disorders, and was therefore most likely a schizoaffective. If
true, this might be explained by a series of brief reactive
psychoses in a narcissistic personality which could not
withstand being confronted with reality (in this case, that he
was not the "superman" or "savior of Germany" he envisioned
himself to be, as his plans and apparent early achievements
collapsed about him). In addition, his regular
methamphetamine use and possible sleep deprivation in the
last period of his life must be factored into any speculation as
to the cause of his possible psychotic symptoms, as these two
activities are known to trigger psychotic reactions in some
individuals. However, Hitler never visited a psychiatrist, and
under current methodology, any such diagnosis is
speculation.