The substantivized adjectives (Субстантивированные прилагательные)
Rule of thumb (железное правило)
The substantivized adjectives + Verb in the Plural
 In English we can combine the definite article THE with an adjective to create a group noun meaning 'all of...' This is common for nationalities. They also take a plural verb.
'The British are coming. The British are coming.' (They...)
The blind, the deaf, the sick, the mentally ill, the handicapped, the poor, the rich, the unemployed, the old, the dead
Most other adjectives cannot be used in this way. You cannot normally say *the foreign, *the happy, * the disgusting
Exclusion: The substantivized adjectives + Verb in the Singular
The deceased – покойник, покойники
The accused - обвиняемый, обвиняемые (в суде)
The military - военный, военные
A BBC news report:
The Ukrainian military claims to have shot down at least six Russian aircraft and lost at least forty of its troops