Im sad your dad is having such a hard time showing you his love, you sound very sweet and caring to me. Its smart of you to see the disconnection between you and he to be something going on with him, and not yourself. Depressed people sometimes blame themselves for things its not necessary to, and that causes a lot of the symptoms to exacerbate.

With it being your dad who is having the issue, there isnt going to be much you can do to encourage him to change. Would he sit down in a heart to heart with you where you could explain your feelings and express you'd like to be closer to him emotionally? Or would he think that was silly?

Aside from that, be considerate of your own feelings. It hurts and you feel a disconnection from something you want and need. Your dad is kind of putting you in the place of being the adult by understanding his needs, and you are a legal adult, and he, in return, is affected by some distraction preventing him from giving you all his love. Im not sure if any of its fixable. Depends on his willingness to change for you I think. Hope you feel better and keep writing and posting.