I'd agree with Serendipity that the Manukan food is probably the best option you have, I did have a browse through those sites & couldn't really see anything better.
I would imagine your ham has been deficient in protein already so it would be important to supplement daily, in addition to this mix, it's rare for dwarf hams not to enjoy mealworms so two or three a day would be fine, a few extra sunflower seeds would be good too, if you can get them pumpkin seeds also in addition to the other seeds Serendipity mentioned, not all at once & each in moderation but a few extra seeds of one type or another daily would be fine.
Going through the treats on
this site I did find a few healthy options, there seems to be plenty of mealworms, sunflower seeds & some shrimps so you should have no trouble getting those, a nice extra to give now & then would be the burgess country garden herbs & mountain meadow herbs, not as a main diet but a little sprinkled in the cage maybe once a week is a good supplement that most enjoy a nibble on, I also found some
buckwheat there which is a really good food for diabetes prone species & most enjoy it so you could use that as a treat rather than the sweet, unhealthy options in addition to the other seeds.
I'm not entirely sure if
these are just apple wood sticks or are actually flavoured wood but if plain apple wood they're good for chewing, not all hams will chew wood but it may be worth a try.