Disability Travel - Jet Blue seat assignment with leg injury

My traveling companion just fell and badly hurt her knee. Surgery was narrowly avoided, but a cast was not. We're flying on Jet Blue next week for vacation, presently booked in middle/window. Does anyone have experience with JB getting reassigned to seats that will allow for full leg extension for a longer flight? Do I need a note from a doctor to secure an accommodation? Is it better to call asap or close to departure?

As for the practicalities of seating, is it better to get an extended leg room seat, or be on the aisle at the front of the plane?

Any insight/help would be appreciated. Thanks.

Either phone the airline or check on their website what their requirements are. If your friend can't walk far because of the cast then you may find it worthwhile booking a wheelchair from check in. They will take you from check in, through security etc to the plane.

Hope you get sorted.

Definitely get a wheelchair at departure and arrival. IMO, an aisle seat on the bulkhead is best for a person with a leg injury. Do call and see what JetBlue requires to change your seats. You might have to change only the injured person's seat and not be able to sit together, but that would be a small inconvenience to the person who has to keep the original - for the comfort of the injured person.