Warning: spoilers ahead for Episode 7 of Arrow Season 6, called "Thanksgiving."
Oliver's life got a whole lot more difficult in "Thanksgiving" thanks to a number of complications that suddenly hit him all at once. FBI Agent Samanda Watson, who has been trying to amass evidence that Oliver is the Green Arrow all season, finally made her move on him and had him arrested. On the Team Arrow front, Oliver learned that Diggle had been dosing himself with illegal steroids to compensate for nerve damage, and he was out of commission as the Green Arrow. On top of that, Cayden James returned to the mix with Black Siren as his crony, and they caused a lot of trouble for Team Arrow at a very inopportune time. All of that said, one good thing happened: Thea woke up from her coma.
Poor Oliver has been missing his baby sister all season, even if Willa Holland has only appeared a couple of times. He really needed a win by the end of "Thanksgiving," and Thea waking from her coma is probably the best thing that could have happened to him after a couple of hellish days. Unfortunately, Thea's sudden awakening may not actually be great news for Oliver in the rest of Season 3. After all, the timing of her sudden emergence from the coma was... well, convenient.
The in-universe explanation for Thea's sudden awakening is that her doctors have simply been cycling her through different medications to see what might work to pull her out of the coma, and they finally hit on one that worked: Zolpidem. Felicity went on to say that Thea woke due to a triumph of neuroscience rather than a miracle. Basically, the circumstances of her return to the land of the conscious may point toward an outside influence stepping in to wake her up.
The two biggest villains of Season 6 to date have been the genius Cayden James and the drug dealer Dragon; one or both of them could have devised a way to wake Thea up from her coma in order to strike at Oliver. After all, he's both a prominent figure in public as the mayor and the original hero on the Arrow-verse vigilante scene. A target is always going to be on his back, and Thea is an easy way to strike at him.
What more convenient way to hurt Oliver than to wake his little sister up from a coma and then harm or even kill her? Even if she wasn't woken by a villain, she's still a target. I'm starting to hope that Thea runs away to join Roy as soon as she's well again. Colton Haynes is likely to return in Season 6, and Oliver mentioned him in "Thanksgiving." Thea deserves a happy ending, and eloping with Roy might be the closest she could possibly get.
Of course, Thea's return to consciousness could be bad news for Oliver insofar as he may be seriously distracted. He's been waiting for Thea to wake up, and he may be trying to focus on her in the not-too-distant future. He may be spreading himself quite thin as mayor, substitute Green Arrow, and doting brother. The passage of the anti-vigilante bill (largely thanks to Cayden James conning Team Arrow into beating the stuffing out of fake cops on camera) means that his life will be more complicated in most areas. Who knows? Maybe Thea was affected by some bad guys while in her coma and she'll be a double agent. Thea waking up this close to a midseason finale could mean very bad news. Nothing good ever happens for Oliver in midseason finales.
We're still a couple of weeks from the midseason finale, however, as next week's episode will air on Monday night as part of the giant "Crisis On Earth-X" crossover. The four-part event kicks off on November 27 at 8 p.m. ET, and it will come to an end on November 28. Be sure to tune in to The CW to catch the heroes of Arrow, The Flash, Legends of Tomorrow, and Supergirl in action together.