Tefilo Kehilchoso 4 (14) says in the name of the Igros Moshe OC 3 (89) that one may not publicly conduct oneself in a way different to the custom of congregation in which he is praying.

See also the accepted (green ticked) answer to this question and apply the same principle here: "Generally a good idea would be not to do anything that actively shows contempt for the congregation's practice..."

Your sephardi friend must have another source for his conduct.

Tefilo Kehilchoso 4 (14) says in the name of the Igros Moshe OC 3 (89) that one may not publicly conduct oneself in a way different to the custom of congregation in which he is praying.

See also the accepted (green ticked) answer to this question and apply the same principle here: "Generally a good idea would be not to do anything that actively shows contempt for the congregation's practice..."

Your sephardi friend must have another source for his conduct.

Tefilo Kehilchoso 4 (14) says in the name of the Igros Moshe OC 3 (89) that one may not publicly conduct oneself in a way different to the custom of congregation in which he is praying.

See also the accepted (green tick) answer to this question and apply the same principle here: "Generally a good idea would be not to do anything that actively shows contempt for the congregation's practice..."

Your sephardi friend must have another source for his conduct.

Tefilo Kehilchoso 4 (14) says in the name of the Igros Moshe OC 3 (89) that one may not publicly conduct oneself in a way different to the custom of congregation in which he is praying.

See also the accepted (green ticked) answer to this question and apply the same principle here: "Generally a good idea would be not to do anything that actively shows contempt for the congregation's practice..."

Your sephardi friend must have another source for his conduct.