I made him understand the concealed meaning of the sentence.
Can I rephrase the sentence without the word 'make'?
I taught him the concealed meaning of his sentence.
'Taught' suggests more than for example 'explained' or 'pointed out'. 'Taught' suggests the information has been not only received but understood. After all, if there is no learning going on, there is no teaching going on either -- only attempted teaching.
"I enlightened him on the concealed meaning of the word. A synonym given by this source is "to instruct."
"I spelled out the concealed meaning for him"
"I spelled it out for him"
to explain something in a very clear way with details:
The government has so far refused to spell out its plans/policies.
informal What do you mean you don't understand - do I have to spell it out for you?
This phrasal verb is commonly used in informal contexts. It specifically addresses your use case of concealed meaning most of the time it's used.
I ensured he understands the concealed meaning of the sentence.
Here are some examples of such usage from published literature:
Student comes to the office after morning recess and is escorted to class by home volunteer or designated school personnel (who will ensure he understands task he has to complete in class). (source)
Explain the postoperative procedure, i.e. the observations that will be carried out and the length of time he will have to remain in bed and ensure he understands why this is necessary. (source)
You need to ensure she understands the time restraints or delivery expectations. (source)
When Clarissa returns I will ensure she understands the unnecessary journey her lack of thought obliged you to make. (source)