That’s quite a difficult sentence! Here's my attempt;
The first difficulty is that the subject is the thing the person is aware of, rather than the person (as it is in English), i.e. “Es ist ihm bewusst” literally means “It is aware to him” (but is the equivalent of “He is aware of it” )
The second difficulty is the use of the modal verb, müssen. I think it might be a bit clearer to translate it as 'had to‘ rather than ‘must‘,
Es muss ihm bewusst sein = It has to be aware to him (he has to be aware of it)
Then comes the tense;
Es muss ihm bewusst sein = he has to be aware of it
(i.e. he must be aware of it at this point in time)
Es musste ihm bewusst sein = He had to be aware of it.
(i.e. he must have been aware of it at some time in the past)
Es musste ihm bewusst gewesen sein. = He had to have been aware of it.
(i.e. he must have been aware of it at some point further in the past)
I think, though as Linguistine pointed out – there are too many verbs in both languages
Hope that helps.
ps I’ve used the ‘ihm’ rather than ‘Hans’ to make it clear that bewusst sein takes a Dative object.