Is it permissible to signal with the hand in response to someone who says "Yarhamukallah" to a sneezer during prayer?

Scholars differ regarding the ruling on a worshipper praising Allah when sneezing. Some say he should praise Him to himself, while others say he should praise Him audibly enough for himself to hear. The more preponderant view is that he should praise Allah and move his tongue with it, because this is established in the sound Sunnah, and because praising Allah is a form of dhikr (remembrance) within the prayer. It is not obligatory but rather recommended. As for saying "Yarhamukallah" (may Allah have mercy on you) to someone who sneezes during prayer, it is impermissible. And as for the worshipper responding to someone who says "Yarhamukallah" to him, it is neither obligatory nor recommended. Some Shafi'is have permitted responding using a third-person pronoun to avoid addressing a human directly.