I have no experience in this field, but I cannot imagine that the editing process would be different.
If I understand this correctly, then your main concern is that the edited version of the translation could diverge too much from the original work. That's not nice, that's true, and people reading both version will recognize that, maybe even getting upset about it, but from the publisher perspective I have to ask: so what?
Many English books are translated to German and I know many discussions how the translation differs and that it would be better to read the original version (Lord of the Rings, Song of Ice and Fire to name just two examples). Probably you know these discussions with Hebrew translations, too.
My point is: No matter how much the publisher tries to keep the translation true to the original work, people will complain. That's life, you cannot suit them all, and the publisher knows that.
So if the publisher has the choice to make a story better (i.e. selling better in the opinion of the publisher) by sacrificing the accuracy of the translation, why shouldn't the publisher do it?
The one who (might) cares about it, is your friend. And depending how much he cares about it, he must control these edits. Which means: there must be something in the contract giving him this power.