Yes, it probably can, but it will depend on the DM's ruling
In normal English usage, when we say something is destroyed, that usually means it has suffered quite extreme damage, beyond any effective repair; and if we were to use it to describe the body of what had been a living creature, it would strongly suggest that beyond simply being killed the body had suffered quite catastrophic damage and probably no longer resembles a body at all.
To "destroy" or be "destroyed" is never given any special definition by the rules of the game, so we rely on the context it is used in and the normal English meaning to understand what is meant when something is destroyed. However, based on how the term is used within the game's text, it seems most likely to me that "destroyed", in relation to the undead, is used to be equivalent to being "killed" - and the word choice is simply because the writers think it does not make sense to say that an undead creature is "killed", because they're not strictly alive. On inspection, the game's text is pretty consistent in that it avoids describing undead as being "killed", only "destroyed". A smattering of examples from monster descriptions:
[...] the periapt of mind trapping doesn’t restore the alhoons to undeath if they are destroyed. Instead, a destroyed alhoon’s mind is transferred [...]
[...] they quickly dissipate when the atropal is destroyed.
A zombie might stumble into a fast-flowing river to reach foes on a far shore, clawing at the surface as it is battered against rocks and destroyed.
A boneclaw can’t be destroyed while its master lives. [...] the boneclaw is permanently destroyed.
Destroying the crawling claw while it is away from the body kills the murderer.
A death knight can arise anew even after it has been destroyed.
And so on. The same language is used in other contexts, such as with magic items; for instance, the description of a certain artifact from Curse of Strahd mentions "destroying" Strahd, as opposed to killing him:
The Sunsword’s special purpose is to destroy Strahd, [...]
The Bonecounter from Sleeping Dragon's Wake uses the language:
Whenever this weapon is used to destroy an undead creature [...]
Neither of these items has any special property that would more thoroughly obliterate an undead creature beyond their normal ability to hit things.
The description of the Grave Cleric, as well, states:
Followers of these deities seek to put wandering spirits to rest, destroy the undead, and ease the suffering of the dying.
In full context, I don't think there's any reason to believe that the "destruction" that would be caused to a ghoul by a Cleric's ability to Destroy Undead is intended to be more thorough than the "destruction" that would be caused by thwacking one a few times with the Bonecounter. It's simply that you don't "kill" undead creatures, you "destroy" them.
In other contexts - when referring to a killed creature that was previous actually alive - the game does sometimes use "destroyed" to mean a rather more comprehensive obliteration of a body. For instance, in the Death Tyrant's negative energy cone ability, it emphasises that a body might be "completely destroyed":
The dead humanoid retains its place in the initiative order and animates at the start of its next turn, provided that its body hasn’t been completely destroyed.
Or in the wight's life drain ability, which does not work on a destroyed body:
A humanoid slain by this attack rises 24 hours later as a zombie under the wight's control, unless the humanoid is restored to life or its body is destroyed.
There is a fair argument that the game rules are unclear about this, and it is certainly the case that many DMs would describe the Cleric's power to destroy undead as vaporising the unfortunate creatures or turning them to ash or dust; in those circumstances, it does seem unreasonable that a Maurezhi could eyeball a pile of ghoul ash and cause it to spontaneously pop back up into a healthy ghoul again. However, it's also a valid interpretation of the Cleric's ability that an affected undead creature simply loses their animating force and falls down dead without the physical body being any worse for wear.
Ultimately, the rules are not explicit about the results, so it's the DM's call whether or not a "destroyed" undead creature is a valid target for the Maurezhi; but I at least would rule that it is, and normal amounts of destruction are within the Maurezhi's power to reverse (unlike, say, a ghoul that was disintegrated).