I would totally agree with the above comments.
An older person in a care home is likely to eat little, lose weight and have other problems like impaired renal function that all contribute to hypos with gliclazide.
It may be that she does not need any tablet to control her glucose levels, or a gliptin might be a far more sensible choice.
Checking an armful of bloods for renal function and blood count and glucose level etc is useful, but an HbA1c can be falsely elevated if your Mum is anaemic, be all over the place if her kidney function eGFR is under 20 (and the path lab sums for eGFR are inaccurate in frail elderly) and the HbA1c is just an average, not reflecting the variation from high to low which can be quite marked.
Finally, one would use an individualised HbA1c target in all people, balancing risks and benefits - this might be a bit higher in a care home resident than in a young otherwise healthy person (I would never be ageist, but one must first do no harm)
best wishes