Because you are not garnering any profit as such, unless the copyright statement says "for personal use only" (or similar), you can make for a friend .The problem in some cases is someone making one, then three, then ten and so on. I recall someone here a while back saying they actually had half a dozen friends wanting the same item - this then becomes the issue of "where does the production stop?"
It *would* be interesting to know what the status would be IF you bought a second pattern or a pattern for each item made. This would then enable more of the same being produced and one could always say you were the sub-agent of the person who bought the pattern. I suspect legally that would be the way to go around the rules although one needs to know I am not a lawyer
My car was driven once by someone who did a task for me. She had an accident - she wasn't hurt but wrote off my car. When she did this she actually had decided to go off and do her own 'thing'. When she was driving within our arrangement of her doing things for me (I was very ill at the time) she was legally my 'agent' and thus I had to accept legal responsibility for any accident. When she choose to go off on her own that broke this legal standing.
So, if your friend bought a pattern and she asks you to 'help' her make it, you are acting within the purchase of the pattern I would think....
What do the lawyers amongst us believe? I actually would have no particular issue following this arrangement because it appears to satisfy everyone's issues.