You will have to apply for a Visit Visa (B2, also known as Tourist Visa) whether your primary purpose of visit to United States is Family Visit or Medical Treatment. In order to qualify for this visa classification, you'll have to convince the consular officer that you'll return to your home country or country of residence (UAE). This means, they will be looking at your social, economic and family ties while adjudicating your application during the interview.

If you seek for Medical Treatment, on top of the above requirement, the consular officer may ask you further documents at the time of interview, which may include -
- Reason for coming to U.S. (why not other countries which offers almost the same standard of medical treatment as in US
- Medical diagnosis from the local Physician eg, reports, treatment history etc
- Letter from Medical Facility in US, stating that they are ready to treat your specific ailment detailing projected cost and length of treatment
- Evidence of financial resources which shows you have enough funds to cover the treatment cost, living cost etc

Qualifying for a U.S. visa is definitely not easy. However, you should not give up your hope as thousands of people like you qualify for it every day. Seeking for Med will make your case harder but if you qualify for a Visit/Tourist visa (without mentioning them that you're coming for treatment), you'll not have any problem undergoing treatment. I mean you do not have to apply for change of status or anything as B2 visa is good for Treatment as well.

hope this is helpful.