The curled leaves are rose sawfly - a tortrix moth larva.....but yes, broadleaf weedkillers act systemically and work over a period of 6 weeks or so (although the initial dieback happens within 10 days). The leaves will yellow, then fall off and the canes will eventually blacken. There is not a great deal you can do apart from watering since this will have to work its way out of the plant system (it is not a given that all the roses will die - some plants take several applications). What weedkiller was it? Do you know if the active ingredients were trichlopyr? 2,4D?

Water! And then more water and then water again. You need to flush their systems and they need a lot of water to do that. Don't be surprised if in the near future you see some very distorted looking growth on them. That is a symptom of herbicide damage. There may be some very reddish growth that resembles a witches broom and the leaves will be crinkled and distorted in shape. These are often signs of the Rose Rosette Disease but are also caused by herbicide spray. Just cut them off and let the plant regrow from there. It may take a couple of times but it should eventually clear up as the plant gets the toxins out of its system.

As for the sawfly larvae, there are insecticides for it BUT at this point I would not suggest using any kind of chemicals on your roses because of the weed killer issue. That also includes fertilizers. They need time to recover before you do anything else to them. The saw fly won't do as much damage as adding a new chemical to the mix at this point. Don't remove any leaves either. They need the leaves to feed and shade the plant.

You may not be able to save all of them but there is a good chance you can save some of them. I had a neighbor who sprayed RoundUp willy nilly around his yard and got my roses. It took a lot of time and patience and water but they did eventually come back. And please, make sure your husband can't get his hands on any more weed killer, lol!