I don't have any current suggestions, been decades since I did it.

Suggest your friend narrow it down to where he/she wants to it, and what sort of animals to view? Also the price range they are interested in? As the outfitters will vary from budget ones, to extravagant luxury safaris.

For example Kenya is or was excellent. Ambroselli under Mount Kilimanjaro, the Maasai Mara plains, good during the migrations (September / October ?). Tent camped in both. An island on Lake Naivasha was also excellent. Kenya has some problems at the moment though.

Tanzania, the Serengetti Plains (never been to them, but they're the same as the Maasai Mara), Ngorongoro Crater is excellent but I don't think it is tent camping.

The Okavango Delta in Botswana, good tent camping safaris there.

Sorry can't suggest any photo tourism safari camping outfitters as the ones I used were too long ago - 1994, 1988.