We say prayers before meals sitting and when many are with us, standing. Thank God your wife does the sign of the cross and folds her hands. My mother taught us this, but when she remained in the New Order, she tried holding hands like the "Waltons". I had to instruct our children what is Catholic and what is not and to keep their grandmother in prayer to go back to the sign of the cross and the folding of hands.
When it came time for the meal prayers, we and the children did what was proper and surprised my mother and step dad, that we did that and did not hold hands.