What to do when the client supplies the lender...and it's not working!

I usually don't go on rants about other Real Estate professionals... well except for REO agents, alarmist inspectors that also do repairs; unprepared Title officers...other than those folks. My issue today is one that is happening too often . We have a client that has purchased several investment properties over the last several years. He has great income and outstanding credit. He also has a "built in" loan officer. From the first deal we did with him (that crashed because his lender couldn't perform!) every purchase has been amazingly difficult. This investor "insists" on picking the Title Company (out of the area), communicates poorly, outsources all his work (processor in one State, Doc prep in another, him in a third) won't back up his promises, and changes his requirements mid-stream. Every deal requires an extension, putting transactions and earnest money in jeopardy. We've tried to "tactfully" explain this issue to the client, but to no avail. We don't want to jeopardize our relationship with someone that is good for 2-3 homes purchases per year. But................., we are starting to look guilty by association! The shame of it is that 99% of the lenders we see are great. They, like us, want to do a good job and take care of their clients. In our market, which includes all of Tooele County but primarily is Tooele City, Stansbury Park or Grantsville UT, I can refer a client to a lender and never lose a wink of sleep. We are able to recommend lenders that have experience and that we have had good experience with through our clients. My concern is that in this case, the lender may be telling the client that we are the issue, and the reason for poor performance, delayed closings, and an overall sloppy transaction. I'm thinking it's time for a heart to heart with this client, right after this one closes...if it does! So, what do you do when the client brings their own loan officer, and they aren't performing?