Has your son met the income requirement for at least 3 years (1 in Quebec) and has he been selected in the lottery for the parent and grandparent PR program? The test that she will need to have done is A1C which shows her average glucose level over 3 months. Is she actually a diabetic? Does she need insulin? If she needs insulin that will likely be a problem. Does she take medication in pill form? Diet and exercise makes a huge difference so she should be following a diabetic diet and getting more active. The medical will also look for damage caused by her uncontrolled glucose like kidney damage, vascular damage, nerve damage, etc. Diabetes doesn't exclude someone for PR.