Okay, let us try this; cut that stem off an inch from the plant. You should have an inch of that 'hardwood' left. Allow it to 'dry' or scab over for a couple of days more. We are going to try to root the whole plant as well as get some baby plants going from a leaf.
I'd use a rooting hormone, I prefer the dry powder but this stuff albeit controversial in efficacy still seems to add a measure of protection/insurance. Nestle this bottom of the plant into POTTING soil. Not garden soil. I would get a shallow clay pot for this guy. 4" to 6" deep and at least 8 to 12" diameter. Moisten the top 1/2 of soil. No rocks below the soil, just soil goes in your pot. Purchase a few little pots; 4" to 6" diameter more shallow than the diameter to use for the leaf chunk clones.
Since this guy has been out of doors this whole time do we need to try to acclimate it to the indoors? I would wait on taking acclimating it to the indoors. Keep it out of doors for now. Sounds as if you live in a subtropical location? I would plant this aloe in the new pot and keep it out of doors on the patio? Deck? Is there a covered area, roofed area of this deck?
Ideally you should make a little domed saran wrap greenhouse for this plant after settled in the fresh potting soil. Use sticks to raise the saranwrap off the plant. You HAVE to not allow this aloe and it's greenhouse to ever get in the sun. The sun going through the saranwrap will cook your plant. The saranwrap greenhouse keeps the leaves from transpiring too far, too quickly. I mean after 3 months? He is doing very well considering!
If you have no way to keep your plant out of the direct sunlight, forget the saranwrap.
When you nestle your plant into the fresh potting soil, use chopsticks or thin pieces of wood to secure your aloe in place so it is not able to move until the roots have grown enough to secure themselves in the pot well enough that a breeze doesn't knock the plant over, ripping out the baby roots. Stick the chopsticks into the soil in a few places so that the secured sticks can prohibit movement, especially falling over. If you have high wind and no area on your deck for consistent shade we need to rethink this process a bit. But for now,
Moisten just the top inch of soil, not sopping wet, moist. Allow it to dry before watering again.
No fertilizer until this plant is growing well on its own. You will need to keep an eye on this guy's vitals. If there is too much top growth which there is and not enough water storage he will not be able to grow roots fast enough to become a whole plant again.
So hedging bets, I would also take one of those leaves to clone it at the same time. This will ensure you get a plant growing from this poor abused plant! I just love you...
I am sending a few links but we need more information, you know, back and forth to make sure we understand all of the variables and help you make this guy a part of your family, grins!