How can I select an ElderCare attorney who is not the current attorney?

There is an organization of CERTIFIED elder law attorney's and the first you saw should appreciate that you want the best for yourself. They have already made their $$ off of you, so there should be no issue/objection to your seeking an expert out...Be sure you have the new person review the priors work. In our case one sentence was written in such a way that it could have been problematic in the future and what piece of work that was in ( a financial POA) had to be redone. Good for you for recognizing and sensing appropriate concerns and doing something while you can. I would not advise two people working together and having to split fees or charge you more. Also it is a blessing if you can find a CELA who charges based on the form/paperwork rather than by the hour....

What is the practice area of the attorney you've had for years?    Estate planning, trust?   Or some other practice area?   

Attorneys will complement each other when their practice areas allow that, but if they overlap, that would create a more challenging situation.  

The best way IMHO to find an elder law is to search the state bar directory's practice area for attorneys, review their websites and any newsletters they produce, list your concerns, then contact them and ask if they're accepting new clients (most usually are unless they're exceptionally busy or short of attorneys), rates, billing practices (i.e., whether by the hour or lump sum), and other questions you have.

Just out of curiosity, I checked the County Bar Assn. for the area in which I live and found that they do have a lawyer referral service.   So you could also contact your county Bar Assn.

Another interesting discovery was their Senior Law Day free programs.

Do a search in your area for Elder Care Attorneys. You can contact the Bar Association and ask.
Do you have to have 2 attorneys? If your current attorney is not meeting your current needs then you change. Would you continue to see a doctor that is not treating you with the most current methods?
The way to find out if your current attorney would work with another is to ask him. You could say, “ I feel there is a need to have an attorney well versed in Elder Law is there an attorney in your practice that has this expertise and would you work with them?” They will say either “yes there is someone in our practice that can handle this and we can work together”
or you will get another response that will indicate that you need to look elsewhere.