Too much water or too much fertilizer. Unless you've over watered? Same symptoms. Please tell us more detail about what you've done what you have added. This plant was doing fantastically and then something recently changed.
You have to tell us every detail you are able to think of! No matter how small. did you take it out of doors in the sun? Did you use boiling water? ha ha. Did you fertilize with something recently? Does this pot have a drainage hole? What kind of soil is in this pot?
Something changed just recently.
Well I wasn't expecting the drive in HOT weather from Tucson all the way to the beach and back?...did she make sure this plant was never in the sun out of doors? Did she keep the air conditioner on when she wasn't in the car? Just taking the plant from its normal environment was stressful.
When I ordered plants from the nursery, they would arrive in a refrigerated, air conditioned truck. Only minutes from the nursery. What did this plant look like after it arrived at your home after mom's vacation? This was a monumental stressful vacation for your mom's plant. Kind of a cute idea but plants aren't meant to travel around at all.
If she left them in a too hot car (over 85 degrees F) or allowed this plant to sit in a too hot car without enough water, that would cause this majorly unhappy plant. Ask her if the plant ever found itself in direct sun...for 15 minutes? Plants are unable to move to get out of the sun or heat or water to survive.
Please send another picture so we can see how this plant is recuperating? This does not look good, not one bit. Bummer. But plants can surprise us humans! Hope it enjoyed the vacation! Sweet but deadly.
A picture now would tell us if it might make it. Please pop the entire root ball out of the pot and take a peek at those roots, take a picture. Plants in pots have the most fragile part of their anatomy exposed to temperatures; hot and cold. The roots. The roots might have been cooked. Or rotted from too much water because the plant shut down. Stopped the photosynthesizing and uptake of water.
Those roots and the seed look healthy! Ugh, put it back into fresh potting soil! Moisten the roots and cover with newspaper while you prepare the pot and soil. Or is this last picture this plant replanted in the original pot? Good!.
You really dived into this problem! I am impressed, probably not a great thing for the plant but you are getting to know this plant intimately! Very good. I think that this guy needs a larger pot by 2" wider in diameter, perhaps even 3 or 4 inches. Clay.
Then some pruning is in order to reduce the plant's top growth a bit. The roots look just fine. It might have been a response to all the stress it has been through. I'd like to see a fresh picture of the leaves at this point. I also think this should be in YOUR family of plants! Grins!