I’m not sure… If the window and everything around it looks original, the mortar could be added to cover deteriorated brick, just shaped so it has a nice appeal (I can’t see from this angle how thick it is / how far is it sticking out above the brick surface). You can see patched and painted over areas on the house next door where they didn’t care for making it look nice, they just coated brick with mortar and painted the surface.
The questions is, how well they prepared the surface underneath. If it was cleaned properly, all loose and deteriorated sections removed prior to application of a mortar layer, it may stick for a while. However, if it’s already cracking in places and sounds hollow underneath when you tap on it (be gentle
)… it will most likely fall off the wall soon.
I noticed some stains on the second floor foyer’s ceiling, between the skylight and what appears to be an air return port. This could be a leaking roof, leaking skylight flashing or patched holes from a track light…