In my mom's will, it states that I am her "Personal Representative" which is the same as executor.
I assume what it actually states that she
nominates you to be personal representative
of her estate (not of her) after she dies. Such a nomination has no legal significance as long as she is alive and legally competent.
Also in the will, it states that I am her Health Care Proxy. I am wondering if I need to get a Durable POA as well or if everything in her will takes care of all the necessary paper work that is legally binding agreement and is enforceable in a court of law.
Neither a will nor a health care proxy nor a DPOA is a "legally binding agreement." Whether your mother's will is or isn't sufficient for any particular purpose is obviously impossible for anyone who hasn't reviewed the document to determine. If she is concerned about the sufficiency of her will for any purpose, she should have it reviewed by a local attorney. If you have concerns, you can encourage her to do same. You could even hire an attorney yourself to review the will, but an attorney you hire couldn't do anything more than give you an opinion about the document.
I'm guessing a lawyer didn't draft that will because designating a health care power of attorney (proxy) in a will is completely useless.
I disagree. While it might not be a good idea, there's nothing that prevents the two documents from being combined.
I believe these are 2 seperate documents. One being her Will and the other being her health care proxy
This contradicts what you wrote in your original post. Have you actually seen these documents?
After seeing that, Would you advise still get a Durable Power of Attorney document from a Elder law attorney from Massachusetts or some other POA document please?
Please review the disclaimer at the bottom of the page as it pertains to advice. Also, no one here can competently give advice to your mother. As noted above, if your mother has concerns about her estate and end-of-life planning documents, she should consult with a local attorney.