H. foetidus tends to not be a very long lived subject but even so, just having planted it in spring is a bit too soon for it to start declining :-) While most hellebores are quite drought tolerant once established, they will need some supplemental irrigation to get established, especially under the canopies of large trees or in dry summer areas. Overhead irrigation is the least preferrable (development of fungal issues, timing, quantity, etc) but a periodic deep soaking through the summer would have been helpful.

As with any other evergreen (or so-called 'evergreen') plant, old leaves do die off and turn brown or black. They can be removed as that happens or with H. x hybridus (not orientalis - that is an incorrect label), uniformly cut back in late winter or as the flower buds develop. Fresh, new foliar growth will be rapidly produced at that time.