I'll keep this short. I bought a mandarin tree back in March, a few weeks before the Covid-19 outbreak. I kept it in my room in London. It grew a lot of leaves and seemed to do well.
Then I left my flat for over half a year. My flatmate kept watering it for a few more weeks and then forgot. He might have watered it once or twice more in the months after.
Now the leaves are yellow/brown and completely dried up although not fallen off. All the branches are brown. Is my tree definitely, 110% dead or is there anything I can do?