Is a cowl too feminine?

It all depends on how your father is like. If your father doesn't really care about fashion and will appreciate the cowl that you make for him, then I say go for it. However, if your dad has a manly appearance about him, then I think that a cowl would be too feminine. Cowls are very popular especially during the winter but I rarely see men wearing them. Instead, you could make a pair of gloves, socks, or maybe a winter hat. You could also make him a scarf instead. I think that it's really nice that you want to make something nice for him for Christmas ^_^.