I agree with everyone else here who has been saying to explore your feelings and be honest with your friend.

One thing I would add here is that your friend is probably grieving and your friend must go through the grieving process to heal from the loss of his long-term relationship. How long it takes him to grieve is anybody's guess, but that will most certainly affect any new relationship. Allow him to grieve and give him that space to do it. If you two do pursue a relationship, it will be much better off when he is over his old relationship.