Yes you can and they can apply for custody and parental rights as well and a judge will take your will highly into consideration, my oldest’s sons never met his dad and hes not on his BC and I have put in my will I wish for my mum and stepdad to have full custody of him and my youngest I’ve put i want my mum and stepdad to share 50/50 custody with his father as obviously I want my boys to be together as much as possible but also to be fair to his father.