There is only one reason to justify keeping him in office. That is the seniority and clout he has from us keeping him in for the last 15 years. Like it or not , that's the way the club works in Washington. I'm not a big fan of his but I'm practical. RI gets more back than they put in with him on the job.
As far as him being a drunk etc , I thought that was a job requirement for a congressman!
Sometimes they sit out a cycle and then come back. I do believe they retain their seniority position relative to committees even if there is a break in their service.
I do not think he was afraid of not getting elected. Its one thing for a previous kennedy seat to be lost do to a dummy who screws up like in MA. Its another thing to actually beat one who is running. He might have had a bad showing in an election but to me that means he only gets 65% of the votes.
Anyway , it will be entertaining to see what he does next.