Give him a copy of your xml file with the xml:lang attribute set to Russian and a copy of Arbortext. At that point the only other thing you have to do is give him any generated text fragments from the Stylesheet to translate. Arbortext Styler will support switching any generated text based on the xml:lang attribute.
Side Note: I don’t accept that Arbortext Editor is “too hard” for casual users. If they do not need any of the power, in Editor properties, set liteui=on it’s much less scary.