All legumes are protein foods, also seitan is high protein and available in many flavours and makes. I take it your friend might not able to manage making her own. Think chickpeas, lentils, green peas, black beans, haricot etc. Seitan is the basis for a lot of "tastes like meat" products, along with quorn. Seitan is a very chewy food, goes well as thin slices in casseroles and stir frys, or as not-steaks with veggies/salads/fries. Does very nicely diced and chucked into scrambled tofu. I make seitan steaks, tenders (a less chewy texture), not-bacon, even pepperoni for pizzas.
Also, she could maybe snack on nuts (unsalted is fine if she needs low salt).
There are soooo many tofu recipes. I have scrambled tofu most mornings, with a couple of strips of seitan bacon and some tomatoes and or mushrooms. That breakfast alone gives me about 25g of protein, less if I'm having a not so hungry day.
Lunch for me is usually a bowl of chopped veggies but I add sunflower seeds and a ground nuts mixture (cashew/macadamia/nutritional yeast - it is gorgeous, and high protein). Nutritional yeast is a dreadful name for a truly brilliant savoury product. 5g of nooch gives you 2.5g of protein. It is a dried flake product with a truly awesome flavour that enhances every savoury dish you chuck it in. Soups, casseroles, breakfasts - most of us get through a fair bit of nooch each week.
I have non-dairy yoghurt with milled flaxseed mixed in and tipped over berries for dessert. Plant based yoghurt is a protein source, a good source of calcium, B12 and D. And I love the stuff.....
I eat an easy 75g per day ie. 1g per kilo of bodyweight and I could push that up without thinking about it.
You need to speak to
@Marie 2 - she is a long term vegan living in the States - she'll know makes of foods etc.