Andrea Taurisano
il cimento
I was quite frank with him and said (nicely) ... "Personally I find her work unappealing and chintzy but I'll do whatever you want!"
You are for sure a very good friend if you're willing to imitate work that's not yours and that you don't even like.
Someone already pointed out that a very good friend, on the other hand, would not ask you to forget YOUR style and personality and copy someone elses.
At least make sure you remind your friend that chances of getting very good results drop when one's forced to do things one normally wouldn't do.. That may help.