My boyfriend has recently been told that his current treatment for eyes has been unsuccessful and he will be probably blind within 6 months. He is already blind in one eye and I'm struggeling with ways to support him - do I automatically take on a role in taking care of him or do I let him cope with this on his own inorder for him to find his own coping mechanisim?

The best advice I can give you is to ask your boyfriend what would be most helpful and supportive to him. Everyone is different as to what they find helpful in situations such as this. It is important that both of you find the coping styles that work best for each of you. You are both dealing with the consequences of these changes and you therefore need to talk to each other about this.