[Rasklad]

As-salamu alaykum.

I have a close Muslim friend who has reverted from Christianity and has now been a Muslim for over 20 years, Alhamdulillah. Unfortunately, the majority of his family (including his wife and children who were already in their mid-20s when he converted to Islam) remains Christian. I observed something that troubled me while he was having dinner with his family recently (this included the presence of his mother and aunts). I saw that he and his family joined hands to pray/say grace over the dinner before eating. His mother asked him to lead and while he said nothing un-Islamic ("We ask God to bless this food and make it good for our consumption. Ameen" [not "amen," but a proper, Islamic "Ameen"]), seeing this troubled me because it smacked of imitating the kufaar. When I asked him if this happens often when he eats with his family, he said that it did and that he did not know that he was doing anything wrong and thought it wasn't much different from when we recite "Bismillah ar-Rahman, ar-Raheem" over our food before eating it. I told him that based on what I know, at absolute best, partaking in this is extremely disliked and, at worst, an act of outright kufr. I can't find anything specifically about this situation online, but it seems this wades very deeply and dangerously into imitation of kufaar.

Can anyone please comment on the permissibility of partaking in this holding-hands-and-praying/saying grace before dinner, if he is always sure not to include anything un-Islamic in what he recites?

JazakAllahu Khayran for all of your help.