What is implied by Tolstoy's calling them not friends, but "nearest acquaintances"?

In "The Death of Ivan Ilyich," prior to being sick and
near-death, Ivan had only acquaintances, not friends.  Acquaintances are formal, but
friends are intimate.  Acquaintances are bothered by death; friends are tolerant.
 Acquaintances go through the motions of mourning; friends actually
grieve.

Before he dies, he will have made one friend,
Gerasim.

Gerasim did it all easily, willingly,
simply, and with a good nature that touched Ivan Ilych. Health, strength, and vitality
in other people were offensive to him, but Gerasim's strength and vitality did not
mortify but soothed
him.

AND:

Only
Gerasim recognized it and pitied him. And so Ivan Ilych felt at ease only with
him.

AND:

Gerasim
alone did not lie; everything showed that he alone understood the facts of the case and
did not consider it necessary to disguise them, but simply felt sorry for his emaciated
and enfeebled master. Once when Ivan Ilych was sending him away he even said straight
out: "We shall all of us die, so why should I grudge a little
trouble?"

The culture of 19th century czarist
Russia was heavily bureaucratic.  To be in society was to be a cog in a machine, to do
the same work--day in and day out--with little hope for advancement or reprieve from
paperwork and frustration.  As such, Ivan treated his co-workers with detachment and
formality.  Private conversations were prohibited.  The society was engineered for
efficiency; close relationships were not productive.  This obviously carried over into
his marriage and family life, for he took all for
granted.

Even his wife and family are acquaintances only.
 His wife and relatives and doctor go through the motions of friendship and nursing, but
they are not friends or nurses.  They are detached, as he is, even in the rituals of
sickness and death.  Ivan is merely something to be tolerated, and
they treat him as a kind of sickness, as a dying man, not as a friend, or even a
person.

They do not acknowledge him, as Gerasim does, with
dignity and respect.  They do not cater to him even when he is ashamed of his condition
and does not want to be seen.  Only Gerasim exhibits a kind of primitive Christian
charity and unconditional love.   Ironically, Gerasim has not been conditioned by the
bureaucracies; as servant of the peasant class, Gerasim has learned to be humble and
long-suffering, kind to the sick.  Only he sees Ivan as a human being, not a cog in a
machine or a sickness unto death.