Entirely up to you, I suppose. We're all just scrambling for explanations to make it make sense, but I expect if this is BS we'll at least see a story exposing it as BS.
Fair enough to wait for a better source, but I'm seeing this in other places too, citing "UK intelligence sources".
But, and this is confirmation bias speaking, this was exactly my guess when I first heard he'd turned around: "guess some family member that he cares about didn't make themselves quite scarce enough and Putins guys have them."
My bet is the other places you are seeing this are either Yahoo or MSN, which is just rehosting the Telegraph's article. That's the only other place I've seen this.
It's kinda dumbfounding to me because like did this dude really think Russia wasn't going to go after family? He's evil but come on, literally everyone knows that they'd do that and more.