Unfortunately I do have any information about the relatives of the person you mention but I appreciate that you are making an effort to try to pass on your document to the descendants and its rightful place, so good luck with that. I think it may prove a difficult task to do though especially if you do not have any relevant details to narrow down your search. I have similar difficulties in searching for my own relatives from this period. However, I would be interested in knowing what the document actually is and if you have had it translated yet.
I took the opportunity to check the VDK database for information on this soldier and incase you haven't had access to this site here is what it produced.
Nachname: Kruska [Surname]
Vorname: Ewald [Forename]
Dienstgrad: Obergefreiter [Rank - one level higher than a British Army Corporal]
Geburtsdatum: 30.06.1925 [Date of birth]
Todes-/Vermisstendatum: 12.04.1945 [Date of death/or missing]
Ewald Kruska ruht auf der Kriegsgräberstätte in Futa-Pass.
Ewald Kruska rests in the war cemetery at Futa Pass. [Italy]
Endgrablage: Block 33 Grab 317
Grave position: block 33 grave 317
The Futa Pass is somewhere between Florence and Bologna (81km).
The rest of the VDK webpage consists of general information concerning the status of the association's activities, donation request, and a contact procedure for them to inform relatives of any news they receive regarding the person. I suppose this service could be available for other people, such as yourself, and there is always a chance that they have had previous contact with the soldiers relatives. I know the VDK will archive information such as documents and photos to pass on to relatives, if they ever establish contact with them. This would be one option to consider; it may not be ideal and the document may never get to any relatives but at least it would be partially on its way. I am not aware of their exact procedure for this, or if the item would need to be the original, or just an digital copy - probably either depending on what you have to offer. You can contact them via their webpage but the site is obviously in German so you may have some difficullty with it; they may be willing to inform you if they have contacts with any Kruska descendants before you do anything, or pass on your address if required. It is all a long shot though.
In some ways things are more obscure now than previously as people become unlisted through anonymous mobile phones numbers and email addresses... Having said that though, there are still 228 telephone references in the German on-line telephone directory for Kruska, quite a lot with addresses, but this would be a tedious and time consuming way of finding relatives without knowing exact details - not to mention expensive. I have tried this course of action several times before and I can say you would be lucky if you received a reply, even if you can write in German. I think people are suspicious - but you may be lucky! The directory also lists internet 'results' for Kruska so it might be worth trying your luck and contact people that way.
It is probable that there are relatives out there somewhere but they are virtually impossible to find. Even if they are interested in ancestral matters they may never find your message so you need to make it as easy as possible to find, but be aware that many people are not particularly interested in ancestral research. Many, especially the older generation may not even use a computer, others perhaps are not very computer literate (and I can include myself here) so this creates difficulties in itself. It is also unlikely that anyone who knows this family would see your message and pass it on if there were no reason for them to search for it. These are problems we all have to suffer.
It is often all a matter of chance anyway. It is therefore preferable to post as much detail on this person as you have and increase your chances. Also, if you have not already done so, it may be worth placing your posting on the Kruska Surname Board, which may be more accessible. If there isn't one you will need to create a new board - I don't think the surname is very common, which is an advantage in many ways.
Entitle the Kruska Surname thread in a specific manner, something like: 'Ewald Kruska (30.06.1925 - 12.04.1945). German soldier buried at Futa Pass War Cemetery, Italy' (I think that is as much as you can fit into the heading box). Consider editing your current heading in a similar manner as this would give immediate recognition to your posting (in any language). This would also mean a 'search engine' would display your message with the precise details of the person as a heading and make it more prominent.
I hope some of this will be helpful,