My concern would be that she might not be producing enough milk for the kids just now if she is not well. I would always at least check her udder every day, and milk her once a day if she has some milk in it. Are the kids happy and content with full tums? Are they growing well? With triplets, you may need to supplement them by giving them a bit extra milk as well.
A good trick to get some milk from her, or to establish that she is producing milk, is to leave the kids with her until last thing at night, then shut them in a different shed overnight. Then first thing in the morning you can milk her, and get some idea of how much she is giving, and also some milk for you if you should need it! At four weeks the kids are more than able to cope with being away from mum overnight.
I would try bringing some extras into her diet- vegetables such as cabbage, carrot, apple, turnip chopped up, greens like curly kale. If you have any plants with buds on try her with those. Its hard to get green things this early in the year, but if it is warmer with you, there might be buds on hawthorn bushes, or flowering current bushes. If not, you can always try holly or even ivy as long as it not poisonous and has no berries whatsoever on it. Even a beech tree with dried last years leaves on can be quiet appetising.
I would ask your vet if he can give her an injection of calcium- the brand we get here is called Calciject, and its what the vet would normally give a cow for milk fever. It definitely won't do her any harm, and might well give her a boost. We have just given some today as it happens to my 2 milkers- one kidded 2 weeks past Friday, and the other a week past friday. Kream who kidded just over 2 weeks ago, is looking ok, but a bit off colour, not her usual bright self, and her calcium levels will have been depleted because she had 3 (and a half) kids, plus she has been giving 6.5 litres of milk a day. If you feel confident at giving injections, you can give to her yourself just injected under the skin, but it is best to warm the calcium slightly before injecting it. If you ask the vet to do it, he might inject it straight into the vein instead.
It might also be worth giving her a vitamin B12 injection which will stimulate her appetite.
Don't know much about that wormer but I will try and find out!