hi, Bergamot, black pepper, eucalyptus, geranium, juniper, lemon, neroli and rose are very good, in baths, massage and vaporiser, you need oils that help with blood flow so stimulating oils , as diabtics suffer with poor circulation so you need to keep the blood stimulated in all areas also they suffer with very dry skin and you need to be gentle when massaging areas where they inject themselves as it can be very tender. you need the person to watch what happen after the treatment as some oils can effect their blood sugar and insulnin levels.
i hope this has been some help to you
regards
dye