(1) if my non muslim brothers called me for a lunch/dinner for a halal food. Can I attend?(2) whether i can recite allahumma atamani vasqin man saqani after eating the food of him? please clarify.
بسم الله الرحمن الرحيم
(Fatwa: 1251/963=L/1430)
(1) Yes, you can join him:
ولا بأس بالذھاب إلی ضیافۃ أھل الذمۃ (الھندیۃ 5:426، بیروت)
(2) Yes, you can recite the above-mentioned dua after having the meal with a non-Muslim.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband