There is nothing you can do to make an unreliable character more reliable. Either bite the bullet and put up with it, or kick him. I have my own problem player of a similar vein, although it is less too busy playing other games than it is the fellow just can't keep a schedule. (example: game is set for a certain date. three days prior and I am assured he will be there. Ask the night before and am assured he will be there. Day of the game he can't make it because he scheduled something else at the same time. Generally work, he's self employed).
Now, on to the issues in the game, not paying attention. Well, what does he want to get out of the game? Does he want more social encounters? More combat? Is he bored? Is he just distracted by his phone? Again, some of these things can be fixed. Adding in more of what the player wants will generally get them more involved, but distractions... Make it a rule that the phone stays out of the game. Naturally, exceptions can be made for legitimate reasons (re: work could be calling. Family member could have medical issue. Significant other is pregnant but you really wanted to game and you're pretty sure she isn't going to go into labor for at least a few hours but just in case...) (Side note, have had all of these happen to me at least once... )
Other anti distraction rules that sometimes help include: No non-game talk during game time (save it for breaks). Significant others are okay to visit, but if they are a distraction will be asked to leave.