It is not native, being a Chinese holly cultivar, Ilex cornuta 'Burfordii' . It is also not considered invasive though, so maybe removing the one that died, and pruning the existing, while adding other plant variety could be an option. If you would like to provide a photo of the area, it could help us to recommend replacements.
Most evergreen holly species are considered full sun plants, so that is probably why it got a bit leggy in the part sun conditions in the summer. There are not many native densely growing evergreens that will thrive in those site conditions, but you could look into American holly, Ilex opaca, if you wanted to maintain it as a hedge. It is a large tree normally, but many hollies can take pruning well. There is a dwarf variety called Ilex opaca 'Maryland dwarf' that you could look into if the heigh requirements are short, but they can be difficult to find in area garden centers.
There are native mountain laurel ( semi-evergreen, no berries) that would do well in the light conditions, if the soil is fertile, consistent moister but also well draining. Kalmia latifolia species and cultivars, but they are not a dense hedge form like the Burford Holly. You could also look at native Rhododendron, but again they tend to have a more open growth habit than the Burford.
To accomplish some screening and benefit wildlife, you may want to consider some different layers of plantings, if you have the space, and can stagger the plants. You can explore the plant list and planting techniques on the mixed privacy screening webpage. Also keep in mind that if the shrubs can't achieve the wildlife requirements in one plant: berries, evergreen shelter etc, you could offer those through a variety of plants from deciduous shrubs, to perennials and ground covers as well.
Is heavy deer browsing an issue? You may want to offer some netting or fence protection as new plants get established.
After exploring some of those options, feel free to send back photos, and ask further questions.