The pot is way too large for it : you need to down size if you want to keep it. The roots likely rotted . I grow cuttings of this size in plastic 12 oz tumblers (I put holes in them of course). But I put a rope wick in mine ( and place tumbler over water reservoir ) to assure that they never dry out: that's death to crotons. The roots will be at the very bottom only, so deeper narrower tree pot is better .
Does it still have leaves? Is it in the same pot?
Your home conditions temp and humidity are perfect. Some part sun would be nice: without it it won't develop variegation. But it will grow mostly green leaves ok.
If you put it outside it will likely dry up much faster, so in the small pot (if you downsize) you'll need to watch it ev day.
In general crotons can take tropical dappled sun, even direct sun and very hot temps in the 90's are not a problem. But no hot noon sun: that bleaches the color out of them. So perhaps you can try positioning it in the courtyard on the weekend when you can watch for a best spot in semi-shade from the building?
