Halal Food In Vietnam

Where does your friend live? Actually it's quite easy to find halal restaurant in District 1.
Your friend can find some halal restaurants near the mosques. I've been to some mosques especially in the District 1 and there were some halal restos and small food stalls there. As far as I remember, there was a small family-run Malaysian/Indonesian resto near Ben Thanh market as well.
But I think sometimes it's a good idea to cook our own meal to assure the foods' hygiene and halal-ness

Thanks Aniskuma for the helpful reply...

He is residing near Majestic Hotel, and yes i agree the safest option is to cook on your own.

Many Malaysian and some Indian restaurants in D1 serve Halal food.

Halal restaurants in Saigon

vegetarian food is an option too.

I think so many restaurant for vegetarian