i am an ovel just finished the shloshim and my nephew is having a bar mitzva on wednesday in lakewood and i would like to know if a i could go to the bar mitzvah and b if i can go to lakewood for the shabbos kiddush ?
During the year of Aveilus for a parent, you should not attend the Bar Mitzvah. You can stop in and say Mazel Tov, but not participate.
A kiddush may be attended on Shabbos.
See Rama Y:D 391:2, CHochmas Adam 166:2, cf. Pischei Tshuva ibid, s”k 5.
Gesher Hachaim pg. 233, with regards to attending a simcha on Shabbos, especially when it is not for a meal, rather a kiddush.