That part that really gets me is that the slave can't seem to even comprehend his own existence. Free him, and he'll remain a slave, since it's his mind that is enslaved, not his body.
I hope that that at least alleviates the suffering that someone with a different mindset would experience - but it makes it much harder for the people viewing it from the outside. And it also adds a huge risk of people making it worse for him physically, in the name of making things better mentally.
If it were me I would not start by freeing the slaves (they have no skills for the outside world), I would start by requiring masters to educate them (at least minimally - basic math, and reading, but not fact based education). The next step would be requiring a government mandated fixed salary per slave (let them build up some savings before having to subsist on their own). Only after that would I actually free them.