Solgar are a really good company for nutrients and herbs. If your Mum doesn't like taking 'tablets' you could use tinctures instead. These are liquid form and you add them to juice or water. Black cohosh is good for sweats, it is the most commonly used one, however, it doesn't work for everybody, so red clover is a good alternative.
Long term though she should be looking at her diet. Plenty of leafy green veg eg spinach for calcium, iron, magnesium. Loads of brightly coloured fruit and veg, eg peppers, tomatoes, sweet potato. These are all high in natural plant osetrogens which can help with menopausal symptoms. Soya products are high in phytoestrogens too, so soya fruit shakes, soya stir fry that type of thing. As your natural hormone level decreases you can start to lose the tone of your skin as well, so plenty of seeds, nuts (not peanuts) and oily fish will nourish the skin and help brain function.
It goes without saying water, water and more water is very important too.
Coffee and alcohol can increase hot flushes so avoiding these for a while should help. Herbal teas will help to flush out excess fluid and calm the nervous system. If she needs a drink then vodka and gin are about the purest alcohols, red wine is particularly bad for hot flushes.
Hope this helps a wee bit - best thing to do is some research on the net and try to find a herbalist or natural therapist near you - Mum's never listen to us but they always take the advice of someone else! Their just getting their revenge for when we were teenagers!