This is about whether or not he can still walk, not about the specific circumstances of the helicopter on the south lawn. I am flexible about where it goes down, but will he be walking unaided on his last day in office is the core of this question.
1,000Looks like he left by car, but resolves YES. https://news.sky.com/video/biden-leaves-white-house-for-the-last-time-as-he-accompanies-trump-to-inauguration-13293121
Following the ceremony, he then walked to this helicopter outside the Capitol to leave DC. He was holding his wife's hand part of the way (as was Trump), but he doesn't seem to have been leaning in her or anything, so I'd be inclined to count it even if it wasn't for the first example. https://youtu.be/DwkdAilHsC0?si=LV1B20DYb2eFYXMz&t=3m7s