Person I traded with went AWOL.

I traded with someone with low feedback and they sent first. I received his cards and sent mine out over 6 weeks ago. He hadn't been on the site for 5~ weeks and then finally showed up on the 20th, said nothing, and didn't mark my cards received or anything. It's just kind of annoying having this trade open in my trades list when I'm trying to juggle a bunch of other offers. Plus I'd kind of like the positive feedback lol. Is there a reasonable time frame to where I can just assume he doesn't get how the site works and "cancel" the trade? I tried messaging him to make sure he got my cards but got no reply.

Trade in question - http://deckbox.org/trades/94056?s=35058