The LFS person may be giving the best advise he or she knows.
In that case - that person isn't necessarily lying.
Or if it's clearly bad advise to pry a handful of cash from your friend for unneccesary equipment - bring this to your friends attention.
It really all depends on the advise given, who is giving it and for what reason.
There's more than one way to skin a cat, especially in this hobby.
Sometimes, as mentioned, it takes a couple of poor choices and having to deal with the results of those choices, before a person understands.
Ask your friend this ....
Is the LFS person asking your friend questions, or just giving advise.
If the LFS is not asking questions about your friends tank goals, then I would be concerned.