I was looking for a Martin Sheen movie similar to this, and re-connected to this movie. It's so long ago, but all three characters were (are) moving to me, and very well played. It could very easily have been sappy or preachy, but it played quite well.
I watched this when I was "between", about 22-23, beyond teen-age angst, but not a grown up parent. All three characters spoke to me. Truly one of those "open filming" movies that were shown 1971 approximately, and now they cut or fuzz over, topics or body parts.
I guess I remembered Bonnie Bedelia strongly from this movie, and she had not been in many movies, particularly just after that. If I find a place that owns it, I will let you all know.