Should I find husbands siblings

My husband was one of six children removed from his parents in 1964. I believe that some or all of the other siblings have been in contact with each other. My husband's adoptive parents chose not to keep in contact with his older siblings. My husband says he has no interest in finding his siblings and that if they wanted to know him they would find him. My husband was very close to his adopted mother and I know that when his sister found her natural parents it was upsetting to her mother. I also know that he has a deep sense of abandonment that I believe is a factor in keeping him from looking for his sibling. I truly believe that he is afraid of being abandoned again by his siblings even though they didn't abandoned him to begin with.
My concern is that my husband has some major health issues (he is epileptic and has a blood clotting disorder). We have a 15 yr old son and a 14 yr old daughter and I have tried to explain that he doesn't need to have a relationship with his natural siblings if he doesn't want to but that he should try and at least find out if they have any of the same kinds of health issues. He could be providing them with helpful information also.
Here is what I know about his family there are five siblings and one-step sibling. They were born in Guthrie County IA from 1957 -1963 (step brother born 6/13/57 adopted in Decatur Co, brother born 4/27/59 adopted in Carroll Co, brother born 5/1/60 adopted in Guthrie Co, brother born 3/20/61 adopted in Audubon Co, sister born 3/31/63 adopted in Webster Co. My husband was born 2/18/62 adopted in Henry Co). The children were removed from the home in 11/64 and taken to the Annie Whittenmyer home in Davenport IA. It is my understanding that his mother may have been pregnant at the time so he may have another sibling out there. His father died 1-3-65 at the University of Iowa Burn Unit.
My husband has told me on several occasions that I can find his siblings but he doesn't want to see them. I would not want to do that because I would not want to hurt them by finding them and my husband not wanting to see them.
Am I just being selfish wanting him to find them so that he can have some closure? I truly think it would help him a great deal in dealing with past hurts. Not to mention the fact that I want my children to have a complete health history, which they can't have without him finding some information out from his side of the family. With his clotting disorder, it could even be dangerous for our daughter to be on birth control since one of its side effects is blood clots.