There is no doubt that Lear values his relationship, such as it is, with his daughters. They are his heirs to his kingdom: they represent the future to him. If he can safely pass the scepter of the kingdom to them, knowing that they will continue his dynasty, he can rest easy and die in peace.
However, it is clear that Lear values relationships beyond those with his daughters. First, he is quite willing to cut off his relationship with his youngest daughter when she won't offer him the lavish praise he desires, so he hardly feels dependent on her for a relationship. Worse still, he seems never to have gotten to know any of his daughters very well. He is too easily deceived by the wooden speech of his eldest daughters, who use exaggeration and cliches in professing their false undying love for him. If he had really seen them or known them at all, he would have understood that their hearts did not mirror their words. Likewise, if he had truly been able to see Cordelia, he would have understood the reality of her love for him.
The king is too used to being flattered, suggesting that he has been dangerously divorced from real relationships for too long. He has been so used to power that he has begun to believe he is beloved for himself, not for what he can offer people.
However, Lear does show a capacity throughout the play for engaging in and valuing relationships. He is close to his Fool, even to the point of calling the dead Cordelia "my poor fool" at the end of the play, as if the two have merged as one in his mind. He also engages in relationships with people like Gloucester and Tom o'Bedlam (Edgar) as his life unravels.