Yes it is possible, GIS data is spatial data which is having the information of Geographic corordinate system and project coordinate system.
Lat/Long always gives the x,y in GCS. So using arc objects you can search the assets intersecting the dummy point created using the lat/long, actually there are multiple ways to handle this you can use the buffere feature also
I am not sure why your GIs expert said no to this, ask him more details why it is not possible.
Cheers
-Mani