I just found this out on the Small Wonder forum, though he passed away 2 months ago.
https://variety.com/2020/film/news/william-bogert-dies-dead-small-wonder-war-games-1203473753/amp/

RIP, Mr. Bogert. He made Dr. Parker look like such a nice man.

Gosh...just in the past couple of years we've lost Mrs. Garrett, Molly's dad, Natalie's mom, Blair's mom, Jo's dad...

:(

RIP, Mr. Bogert. He made Dr. Parker look like such a nice man.

Gosh...just in the past couple of years we've lost Molly's dad, Natalie's mom, Blair's mom, Jo's dad...

:(

And Julie Ann's real life mother as well as Nancy M.'s real life dad and brother.

RIP, William Bogert.

So sad to lose so many people associated with the show recently.

Aw RIP