The question asks: (e.g. He didn’t come only. He’s like that only. He was there only.) (To vote and comment on Quora, visit the link here.)
First usage of the word ही:
Purpose: to mean “only”
वह अभी तीस साल का ही है.
Translation: He is only thirty. (OR He is just thirty.)
Second usage of the word ही:
Purpose: to give stress on a word
(without stress) मैं वहां खड़ा था = I was standing there.
When stressed on “वहां” (“there”), it becomes:
मैं तो वहीँ खड़ा था. (वहीँ is a contracted form of वहां ही)
Correct translation: I was standing there itself.
But many speakers use the first translation in the second context as well:
Wrong translation: “I was standing there only.”
मैंने ही उसे ऐसा करने कहा था.
Correct translation: It was I who told her to do it this way. OR I was the one who told her to do it this way.
Wrong translation: I only told her to do it this way.
The correct forms of the sentences given by you are:
1. It was just that he didn’t come.
2. That’s the way he is.
3. He was there itself.
As you see, there are several available replacements in standard English, depending upon the context. That’s a reason why many people to whom English doesn’t come naturally, prefer to have it easy by using “only”.