I have a friend who cannot eat dairy products but needs to gain a lot
of weight. All the weight-gain products seem to be based on whey which
he can't digest. Are there any effective weight-gain products that are
dairy-free?

I've seen some soy-based products but they seem to have only something
like 120 calories per serving compared to nearly a thousand in the
whey-based products. I'm looking for something in the same range of
calories and fat as the whey-based products.