彼は髪をかきむしりながら泣いた。

he; him; his; boyfriend

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

hair (on the head)

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to tear off; to pluck; to scratch off

while; during; as; while; although; though; despite; in spite of; notwithstanding; all; both; as (e.g. "as always", "as long ago"); in (e.g. "in tears")

to cry; to weep; to sob; to howl