I have been diagnosed over 3 years now and started low carb eating a couple of months after that.
I haven't changed my meal times at all. I doubt it is necessary, and at the end of the day we have to live our lives and not be dominated by diabetes. Maybe you are thinking of the old days when Type 1s had to eat at regular times because of the type of insulin that was available in those days? It is different now, and your mother isn't on insulin. Just eat when you normally eat, but try to avoid snacking as much as possible.
I am retired and don't get up very early. My breakfast (just a coffee with cream) is about 9am. My lunch is about 1-30pm. My tea is about 7pm. Other than that all I have are a couple of cups of tea and lots of water.
Most Type 2's are insulin resistant, and this is known to be more of a problem in the mornings. For this reason I have no carbs at all until lunch time. I used to have a Greek yogurt with flaxseed and very few berries but found even the small amount of carbs were too much for me. My meter told me this. Since skipping breakfast apart from my coffee with cream, my pre-lunch levels have dropped by over half a mmol/l consistently, every day.
As for Metformin, it does hardly anything to blood sugar levels. It helps with insulin resistance and reduces the amount of glucose your liver produces, but all to a limited extent. It is by no means a miracle drug and shouldn't be relied on to lower blood sugars. It is mainly an appetite suppressant so can help with weight loss. A correct diet is the key.
Has your mum got her own meter? If not, I strongly advise her to buy one as without one she will be working blind. Meters aren't expensive and you only need one. However, you need thousands of test strips, so you need to check out the prices of these before you buy. They range from about £7.50 for 50 up to almost £30 for 50.