First, so sorry to hear about your husband. Thoughts and prayers for him, you, your daughter and the rest of your family/friends.
Second, on the GRE, in addition to many schools no longer requiring the GRE, some vet schools take it a step further and say they will not consider GRE scores at all. If your daughter is looking to apply only to vet schools that will not consider GRE scores, the decision is easy. No reason to take it. But if she is applying to schools which are GRE optional but will still consider those that are submitted, I would at least consider taking the GRE is she expects to do well on it (from what you have posted so far, I expect that she would). Improving an application won’t hurt you and it may help you. As you note, better to have an application that is better than it needs to be than one that is deficient in a way that could have been improved resulting in a need to re-apply the following year.
My kids always did well on standardized tests and never spent significant time preparing for them/stressing about them. Other kids cannot stand them (even some who do well on them). From what you have said, sounds like your daughter may not like them. If that is the case (or she thinks she would need to spend too much time preparing) and she is applying to vet schools that do not require them, I think its fine to skip the GRE based on what you have said about her academic record. And given she needs animal hours, I think it makes sense to focus more on that and less on the GRE.