Windows phone user receiving only first letter of group texts

I have a galaxy S7 and I've noticed in the last couple of weeks that when I send a group text to my husband's windows phone, he only receives the first letter of the text.  All others in the group text receive the entire message (inclucing an Android, iPhone, and another Windows phone). He receives the entire message whenever I send to only him.  But with 3 kids, I often need to send group texts to the entire family, so sending only to him is a nuisance. I thought the problem was on his end, but I've read that the same thing has happened to other Android users after they updated their phones. What is the problem and how can we fix it?