Do you know the brand/product name of the fancy shampoo and conditioner she's using?

You could get her the book Curly Girl: The Handbook - I know she might not have curly hair but it's a method of haircare that's applicable to anyone with hair that's in bad shape, especially if it's frizzy. The main steps are to cut out all silicones, sulphates and waxes from her haircare routine, then deep condition and wash with either conditioner (cowash) or a specific gentle type of shampoo (called 'low poos' of which there are many available). There are loads of groups on Facebook she can join that will help her. It's a specific method of haircare with rules to follow, which makes it confusing at first (the facebook groups are great for that) but really simple in the long run.

Curly Girl will also enable her to clean her hair more frequently without drying it out. Cowashing is great for this.