Ok so I just found this out tonight. FI's paternal grandmother passed when he was five years old. A few years later his paternal grandfather remarried. FI's step-grandmother has one son who is married and has three children. He was wondering if we inculde them on the invitation list. Now here is the catch even though this is his father's step-brother they do not celebrate things such as Christmas together. (except the step-grandmother this is her son so she and the grandfather celbrate with this family) I have never met them. Should we send them an invite? FI hasn't seen them in years as well. I am not sure of the etiquette on this arrangment.