Wow, this sucks...
I'd rather not lose either player, but this is clearly a play by the Blues to bring in Broberg first and foremost.
Offering both players offer sheets simulateously is a move to force the cap strapped Oilers into not matching.
The obvious play here in my opinion is to match the offer for Holloway and let Broberg walk. Holloway is the better player and the number they're asking for him is not that much more than he would have gotten anyway. I think the Oilers would be foolish not to match this offer.
While it sucks to let a young defensemen with some potential walk, he's not worth what they've offered him, not even close. I'm not necessarily saying he couldn't be worth that in 2-3 years time if given consistent minutes, but he's only really been notably "good" for a single playoff run, and even then just parts of it. On top of all of this, you get a second round pick in return.
Easily the best move imo is: match Holloway offer, let Broberg walk.