can redkin extreme shampoo fade colored hair

Hi I am new to this forum and have enjoyed reading many of the post and have learned a lot.  I do have one question that i was hoping someone could help with.  My daughter has been getting her hair foiled for 2 years every 10 weeks and natually her color has graduated to what appears to be all  one solid blonde color.  Its beautful but the only problem is that over this time period her hair continues to break off and she can't seem to grow the length back to what it originally was (long) because of the damage.  She uses Redkin extreme shampoo and conditioner faithfully for  at least 8 months and also does the extreme professional protein treatments under the dryer at home two to three times a month along with regualar trimmings. .  The breakage is an ongoing problem but my question isn't regarding that at this time.  I was just curious if the redkin shampoo and conditioner can make her color fade.  Her hair always looks great for about 2 weeks then it fades to almost a completely darkened not bright blonde.  I was considering buying a professional shampooo for color treated hair and discontinueing the redkin extreme but i know it will be at a cost of loss of keeping her hair as healthy as possible while she continues to highlight.  I was wondering if anyone had any experience with this problem.  Unfortunately we live in a small town with not the most  experienced colorist that keep up their education with seminars and etc. so any advice i get from them i always feel less then confident with.   Thanks for any help you can give.