How good was that? I guessed it before you put the picture up
It looks like hops to me - it should feel rough, slightly bristly. There are male and female hop plants, only the females will have the flowers used for brewing, but apparently home brewers are quite keen on getting 'green hop flowers' rather than dried ones so you could ask around if anyone wants them when they bloom. They can look really attractive in the autumn (there is a golden form too) and you can gather the vines with blooms on to decorate your home etc. If you friend likes it tell him/her just to cut it down in the autumn, it'll regrow again, and if it's getting a bit rampant just thin out the growing stems and try to train it into a tree or trellis/arbour/boundary hedge etc. Or if they really hate it they could dig it out and glyphosate any regrowth.