For all the lawyers, I am not establishing a physician patient relationship.
If she's several days into this the Echinaciae and D3 will only help minimally at this point.
There are some case reports of severely ill folks with this who received IV vitamin C (they were in to bad of shape for oral) with impressive results.
Get some vitamin C tablets or lozenges and have her use them frequently like every 1-2 hours while awake, from 500 -1000mg. You will know shes getting too much if she starts to get belly cramps or diarrhea, and then just back off. DO NOT use fruit juice as your source of Vitamin C.
They're are some recommendations out there with Echinaciae at the beginning, but you want to try to find some with the root (rhizome) in it because it is more potent. The other recommendation is vitamin D3 50,000 units per day for 3 days only. if you persist at this dose level, it will cause other problems.
Hope this helps, and prayers sent.