I am in Avelus for my mother a”h, my wifes nephew is getting married, what is my halacha for the weddings, eating at kabalos Ponim, staying for chupa, and wedding itself?
Since you are in aveilus essentially you are not allowed to attend the wedding since wedding bring one to simcha. Although the happiness of the parents of the chosson will be diminished, it would only be permitted if it will diminish the simcha of the chosson himself. You may however attend the kabolas ponim provided that there isn’t music being played in the room. When you are there you may have some of the light refreshments, such as drink salads You can attend the chupah if it is in a different room than the meal, and only when there isn’t music being played. You shouldn’t attend the meal.
Shevet Halevi 6-219 (4), Nishmas Yisroel chap. 19-13, Tziyunei Halacha pg. 513, Hilchos Aveilus (R’ S. B. Cohen) pg. 209-210.