He looks terrible. It's not normal for someone to decline so rapidly in appearance. It's not so much that he's aged (although he has) he looks in really poor health.
He also appears to have lost all control over his world. He barely controls his vices, and walks straight into all traps that are set for him. He also seems to have a simpler mind. Really shallow reasoning. knee jerk reactions to stuff. He's diminished. He seems to do the rocking back and forth more. He's lost previous inhibitions, particularly the wrote begging/begging tweet which he previously saved for special occasions or did off screen out of embarrassment. Even quicker to rage or grievance like this ridiculous ArnoldGate rant which he could have just left alone.
He's basically a confirmed barely functioning alcoholic at this point right? The bank leaks and some days he appears hungover or drunk. Drinking a lot also explains the fast food door dash impulse. So inability to control his inhibitions, alcoholic and lacks any insight so no hope to get help or get his life back on the rails.
I don't know how quick it will happen but the trajectory seems very clear. It would be tragic if it happened to anyone other than Phil. Since it's him I'm finding it interesting to observe a person in such rapid decline. Imagine failing this badly at life.