Relationships and schizophrenia

My son is 23 and has a beautiful girlfriend, she has endured a lot of emotional stress from my son and she has seen psychosis and epileptic seizures, I don't know how to help them they have broken up many times and got back together. I don't know how to explain to her that he has schizophrenia.
She asks is he ever gonna change and I respond this is how he is. She has big goals very career focused and money oriented.
My son mows lawns and that's probably all he will do for a long time. This is good for him because he gets lots of physical fitness all day he comes home exhausted and sleeps a lot. I don't know what to do. He has limited empathy which is related to his MI is egocentric but can also be very caring it is up and down. She is very confused and I don't know how to explain. I just don't know if he will ever have another girlfriend and I worry about his future . He has come so far from not leaving his room for 8 months 3 years ago to having a full time job. He still has social anxiety and some paranoia when he goes out. I think with schizophrenia a partner needs to have patience understanding be caring have a thick skin and be able to help the partner eg prompt to to take mess etc . I don't want to be that interfering mother either it's just difficult when dealing with the MI schizophrenia
Does anyone have any suggestions on how to help??