I agree with you, love is definitely the key, the key to every teaching process, and it can certainly work miracles. I don't know how deep your child's autism is, however, I can speak from my own experience and assure you that any special condition can be overcome to a greater or lesser extent, with continuous work and a lot of love. I admire your dedication to your son, surely your effort will have results. Never give up. Greetings and blessings.