For example, which of the following is considered correct?:
- Don't be like him
- Don't be like he is
There are other examples I can't think of right now where people use him instead of he, or her instead of she etc. It's frustrating!
For example, which of the following is considered correct?:
- Don't be like him
- Don't be like he is
There are other examples I can't think of right now where people use him instead of he, or her instead of she etc. It's frustrating!
Both sentences are correct because LIKE can be both a preposition ('like him') and a conjunction ('like he is').
After the preposition we should use the object pronoun (him, her, me, us, them).
After the conjunction we should use the subject pronoun (he, she, I, we, they) which is followed by the personal verb form.
See Merriam-Webster's Dictionary (https://www.merriam-webster.com/dictionary/like):
LIKE
Conjunction
: in the same way that
: AS
// they raven down scenery like children do sweetmeats
— John Keats
Preposition
: typical of
// was like him to do that
[1] Don't be like him.
[2] Don't be like he is.
"Like" is an adjective in both your examples. The difference between them is that in [1] the pronoun is direct complement of "like", and since adjectives take accusative case pronouns as complement, it must be "him".
But in [2], the pronoun is subject of a finite comparative clause, and since finite clauses take nominative case subjects, it must be "he".