as one who knows little about diabetes, i have to agree the patient should be tested for it and followed for any necessary conventional intervention, but also for the help this might give in adding to/clarifying current state as you continue repping the case to find better similimum.

but, my own developing atttitude makes me look at this case and suggest that, if thuj has presented itself as an effective remedy - it helps - but the patient aggravates, the next reasonable step to take is to re-dose with thuj, but a smaller dose ... much smaller. depending on how severe you judge the agg to have been, if he's been on a teaspoon, drop to a single pellet ... or olfaction, even brief olfaction: the "smallest" dose can be very very small, and if you go too small, there will be no reaction, no healing, but also no agg and you can go to another small-but-not-quite-so-small dose in fairly short order, as soon as you are clear there is no reaction.

as a very extreme sensitive, i have felt that homeopaths seem typically to forget about the importance of the smallest dose, and i have found the healing and gentleness of remedies to be wonderful --- once this factor has been taken into consideration --- just as their aggravations were nearly intolerable with a more normal, or usual, prescription. also as a sensitive, it has seemed to me that homeopaths view "smallest dose" within the framework of "normal" people ... but if one is a sensitive, "small" is much much smaller than one normally encounters. i can't overemphasize the difference it makes to have finally gotten to a dose that is an appropriate size for me.

edit to add: anyway, i am sure this suggestion covers only a small part of the case, but hope it contributes something of use to you.

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"The need to perform adjustments for covariates...weakens the findings." BMJ Clinical Evidence: Mental Health, (No. 11), p. 95.... It's that simple, guys: bad numbers make bad science.