What's wrong with my Aloe Vera plant ?

probably overwatering

the aloe is one of the plants that will turn limp when it is overwatered because it can not get the water it needs from its root system to keep the leaves fully engorged

the brown spots are another indication of excess water

they don't like full summer sun so protect it from the heat of the sun

reduce the amount of water it gets

make sure the soil it is in is on the dry side right now

if the roots have rotted just cut the stem from the rotted base and start a new plant by letting the cutting dry for a few days and then planting it into fresh potting soil

Is it in direct sunlight?

I would say that brown spots are due to over watering it, but since the leaves are limp that shouldn't be a problem.

It might not be getting enough sunlight.

Urinate onto the roots that will provide the nutrients its missing out on