Not when the same Awakened attacks that forced Luffy to fly through the air constantly in order to avoid being impaled by them are sprouting from below and all around him. He'd be too distracted and occupied avoiding those to protect Luffy. Keep in mind that with Luffy giving his full attention to the strings, he was only barely able to dodge them before he found his opening. If Law tries to split his attention between protecting himself and Luffy from those same strings, he's gonna **** up.
I didn't say it WOULD. I said that it DID take Luffy, in the canon manga drawn by Oda, 20 mins to find an opening to strike Doflamingo. When Doflamingo started using Awakening, Oda included "20 minutes later" in one of the following pages, and Luffy was still just dodging around them.
Shambles has only ever worked on Doflamingo when his guard was down. Since Trebol and Bellamy aren't there as back-up it's highly unlikely he'd drop his guard for that to work.
It's been two weeks since Dressrosa...