I have 2 horses that would live on their own - not saying its ideal but they wouldn't get upset by it and both did live on their own before I had them - the one thought she was a dog I think - not great and I do think they live rather unnatural lives, no different to a person forced to live in total isolation.
I also have a couple of horses that no way would live on their own - its not just a 'feeling lonely' thing - they would get terribly stressed and difficult to deal with even though they trailer and ride out alone they need a field buddy to be settled
If you can't persuade your father to allow you to have a small pony or even a goat as a companion I think you should walk away from the idea of keeping a horse at all
Sorry to sound so blunt about this. Its just the way I feel about the situation, I'm sure others will disagree.