As anyone who has experienced HRT can attest, hormones are amazingly powerful chemicals!
Three weeks, however, isn't anywhere near long enough to judge their effectiveness. It was almost two months onto HRT before I noticed any changes at all and even then they were very subtle.. it was about 6 months before I noticed any skin changes. Have patience, Grasshopper :-)
As for the friend still using Androcur... That's powerful (and potentially damaging) stuff! If she got her T levels checked I bet she'd find that there's no necessity for it. I've heard of post-ops staying on low-dose Spiro to kill whatever the adrenal gland produces but not Androcur.