WordPerfect Office Ideas Portal
Grammatik gives bad advice, at least to me. The most glaring example? It advises substituting "you're" for "your" even when the latter is correct, e.g. "your friend." There are other problems, too, e.g. its mania for wanting the object of a sentence to always appear directly after the verb. So Grammatik needs a fix in or before the next version.
You would have to provide a sample sentence. "Give this advice to your friend. " doesn't pose any problems.
To change the strictness of the rules, just open the options dialogue of Grammatik and select another style (or change the current one according to your taste).