"Elle aime bien ses demi-frères."
Translation:She likes her stepbrothers.
The purpose of elision is not how it looks when two vowels collide but instead it is about how hard it is to pronounce them without elision.
Since the final e in elle is silent there is no concern about the difficulty of e and a close together. The L sound which actually precedes the a in elle aime is easy to pronounce in conjunction with the a.
Great discussion on this point. The translation of 'aime' as either 'like' or 'love' does seem a bit arbitrary, and my choice is marked wrong over half the time. Not yet in sync with French standards of attachment. 'Aime bien' downgrading 'aime' from 'love' to 'like' does clarify it somewhat though. Thanks.