re: "Client Disappeared"
Clients are allowed to "disappear." There is nothing wrong with this.
Freelancers get paid automatically whether or not clients "disappear." This is one of the great advantages of using Upwork.
re: "I have a client that I completed work for who messaged to say he was happy with the work and asked me to submit for payment. I don’t think he realizes that he needs to also approve the work on his end and he completely disappeared on me."
Fortunately: You are incorrect.
Clients do NOT need to approve the work.
As freelancers, we receive payment AUTOMATICALLY when a client disappears.
re: "It’s been over a week now."
You used the official green "Submit Work / Request Payment" button over a week ago?
That is good. That means you only need to wait one more week, and then all money in escrow will be released to you automatically.
re: "Will I get paid for the job if he never approves on his end?"
re: "Does this effect my score if he never responds?"
You have completed 13 jobs, and your work history is filled with excellent feedback from clients. If the client never returns and if you eventually close this job yourself, I seriously doubt you will see any drop to your JSS at all.
re: "What do I do?"
Do nothing. Just wait.
If you you click the "Submit Work / Request Payment" button again, then your 2-week waiting time RESTARTS. So DO NOT click the button again.
Will I get paid for the job if he never approves on his end?
Provided he set up a milestone, yes. From the time you submit the work, they can approve it or challenge it. If neither happens, your money will be released to you automatically after 14 days.