Most night terrors are outgrown, however, there is usually a stimulus that can cause them. At 2 1/2, I doubt there is any stress (which can cause them in older children) so environmental toxins can be a primary culprit. Cleaning supplies and bath and body products can cause neurological damage and can cause things like night terrors, nightmares, child behavioral disorders like ADD and ADHD and even memory problems. The main problem with your average product at Wal-Mart is that it has a "allowed" limit of toxin. When used in combination of other things with "allowed" limits, the limit has increased. This is not to mention the combination of toxins that outgas and contraindicate like a pharmaceutical does.
The other issue that usually causes night terrors is lack of sleep. So you have a vicious cycle here with night terrors keeping her awake and causing lack of sleep.
Detoxifying your house will help a lot; especially by changing to a laundry detergent that is considered non-toxic to humans. (There are a lot of things labeled non-toxic that are only considered non-toxic to the environment.) My husband's sleep problems improved greatly after we detoxed the house. HE does use a supplement called RestEZ so I can get MY needed sleep. It is primarily Valerian Root and has a relaxing affect and doesn't make you sleepy or groggy in the morning. A 2 1/2 year old should be able to take it but do your own research. I know it would help your husband if the detoxing of the home doesn't solve the problem.
Detoxing CAN be simple and it can be inexpensive to. If you want to give it a try, I'd be glad to help. Feel free to contact me.
Hope I helped a little C.!