All of us have experienced a partner or two like that over the years.
As GEN Colin Powell once said, "Even Saddam Hussein has value. He can always be used as a bad example." Learn from these referees too - if only - that's NOT what I want to be like in a few yrs!
While some people are in it for the $ and have lost their motivation, there are a great many of us old timers who dress and act professionally, hustle, stay up on the rules, teach and mentor younger officials, etc. Latch on to one of them as a mentor if you like.
When saddled with a "less than stellar" partner of any age/experience level, GIGDGO and hope that in a few yrs, younger officials aren't looking at you and thinking the same thing of you, you are thinking of these officials.
Hang in there and take the high road.