How do I work with Crestor tablets in a syrup for a child of 6 years?

It is not easy to give an answer to your question without any test. It strikes me   that the tablets have a film coating, which is water soluble and not gastric juice resistant. Why does the company do this? I don't know. Either because of the taste, for the sake of stability or to distinguish a color between the different dosages.  

There is nothing else left than the tablets to pulverize fine powder. Preferably after fine making seven to be sure that everything is very fine. The active constituent of Crestor (Ca-salt-)   is very little soluble in water but of course there is not much to dissolve in water to give a bad taste to the whole.  

you let   not   seduced by a Barnum advertising for expensive products???   I would like to use a vehicle described in my Galensich Formularium  

Xanthan gum 0.2 g; After saccharinate 0.2 g; Potassium Sorbate 150 mg; Citric acid 100 mg; Sorbitol 4 G and water up to 100 ml. If necessary, you can add a flavour aroma, which is compensated for e.g. banana aroma.  

Maybe the preparation is reimbursed by RIZIV?  

I find no data on the stability of this product, which is rarely prescribed for children. Therefore, there is no curable form on the market, I suspect.

Make a quantity for a useful life of up to 2 months and recommend to store the bottle in the refrigerator.