Private Lessons + Music Software?

My son is taking private lessons for both violin and piano, and I knew I wanted to supplement with some sort of piano software (not quite sure which yet), is there anyone that is doing both, lessons and software? What are your thoughts? When I mentioned to the teacher that I was interested in supplementing with a software piano program his teacher was against it for at least another four months :confused: . I would just hate for my ds to not be as advanced as he potentially could be with a software program. And since Iโ€™m paying for lessons I would like for them to be worthwhile, and I donโ€™t plan on stopping formal teaching. Would me getting software anyway hinder his progress?

Thanks in advance.