Onion Weeds....Blech

I don't think "onion weeds" is the scientific name for those really annoying green onion type weeds that seem to grow in patches in your yard. We are experiencing a bad case of the "onion weeds" right now. David has literally poured mass quantities of weed killer (it starts with an "R" and ends with a "P") and they still live on. What the heck!?! He goes out there every night to start pulling the little buggers out and then smells like an onion factory for the rest of the evening. He has even asked for ME, of all people, to start weeding during the day. I told him he was nuts and if he just paid for a professional to fix the yard, we wouldn't be in this stinky mess. He's hell bent on getting the yard to look like a lush green carpet on his own. And while I applaud him for his efforts, he is not having much luck. I told him that people make careers out of ensuring yards are green and perhaps he should think about calling one of them. No luck...he's determined to get "his babies" as he call them (the grass) to grow. He told me that it would take two years to get the yard looking nice....we'll we just finished year one. We'll see how year two goes. So if anyone has any tips on obliterating the onions, let me know. My nose and my yard would greatly appreciate it.