Kidney stones and vitamin C

My husband has been taking lots of vitamin C this winter and it has really helped him get over a few colds. When he feels a cold coming on he might take up to 5 grams a day but usually he takes less than that. This week he has developed kidney pain and I have come to find out that his dad had kidney stones. Could he have developed kidney stones because he might be prone to them and he has been taking a lot of vitamin C?

He has cut down on the C (about 2 grams a day) and is drinking Watermelon Seed Tea which seems to help. Any suggestions?

Thanks!