My step dad has been told he. Cant have nuts because they contribute to his kidney stones. Can he have almonds?

Depends. Even people who have had a 24 hour urine study for stones that show high oxalate can have nuts occasionally. The key to a low oxalate diet is to be aware of the items that are high in oxalate and not to overindulge. If he hasn't had a 24 hour urine study, he could mainly focus on increasing his water intake (80-100 oz/day), limit salt (sodium) < 1500 mg/day and go easy on animal proteins.
Almonds are nuts. There is a theory that oxylate in food- including almonds- can cause kidney stones. It isn't clear the theory is correct. Very often, medicine has been wrong about such diet theories. Diet how in calcium used to cause kidney stones now we know a diet low in calcium is the problem. Lot of water, adequate calcium, and less animal protein have more evidence for the common type of kidney stones.
Minimal amounts. Calcium oxalate is most common stone; reasons include: dehydration; excess calcium in urine; excess oxalate in urine; low citrate in urine. Diet: avoid spinach, rhubarb, strawberries, nuts, chocolate, tea, wheat bran, and all dry beans; increase orange juice 8 oz twice daily; add ReaLemon extract: 5 tblspns per day; increase fluid 4 liters/day; only 4 oz meat/day; low salt; 4-5 fruits/day.