You would want to approach this with sensitivity, MDU. H would not want to feel that you are critical or criticizing his parenting skills. Which is why I suggested that you talk with his school counselor to get some ideas and it would help you in that he cannot really target you.
Then after you speak with the school counselor, ask him/her to call H for a family meeting at the office. This way, it will be on neutral ground and you two will be able to discuss ways to support S7 and D4.
I am sure Starsky, Train, and others who are parents will chime in with ideas and suggestions.
