Each is a singular of a plural. “Each apple was delicious” is not the statement of a singular. “Each person can make their own decisions” is a singular under each but speaking of a plural.
And themself is not a word, just as himselves is not. Them applies pluralism, therefore the only grammatical sentence is “each person can decide for themselves”
Each is a singular of a plural. “Each apple was delicious” is not the statement of a singular. “Each person can make their own decisions” is a singular under each but speaking of a plural.
With this usage of 'each' you are iterating through members of a set, referring to all members of the set individually.
And themself is not a word, just as himselves is not. Them applies pluralism, therefore the only grammatical sentence is “each person can decide for themselves”