It wasn't outright patronizing. It was just Eli Chambers being Eli Chambers. He didn't just think he was smarter than most people he met, he actually knew it. So, in a way he was humoring him, but he was also sort of gauging how smart Adrian was.
Eli nodded along with the assessment. "So first we confirm it is in fact living, then rule out the imperius curse, perhaps even by testing what sort of pain threshold this thing has." Which would also determine if it could feel or not - and then if he knew if it could not feel, well that opened things up to a whole new realm of possibility.
He started in on the first test, muttered to himself and scribbling things down until he paused. "That's curious." With his wand he poked at the badge on the thing's top. "I don't believe that prisoners would be allowed any sort of decorative item." Eli carefully plucked the badge off the man's pajamas, being mindful not to let his teeth get him. It might not feel pain, but it certainly felt something struggling as it was against it's bindings.
"Do you recognize this?" Rather than interrupt his work, he levitated the badge toward Adrian for him to examine. In part because he didn't know what it was and also because he figured it would be best to give the auror something to do.