To explain his motives (not justify them), I'd go along with "Invite him so I can shun him in person."
Hubby and received a second-class wedding invitation, too. Dance only, no reception. We didn't figure it out until we walked in on everyone at their tables enjoying their after-dinner stories. Hubby was hurt and I was offended. We left. I've heard since that this is a new trend to maximize gifts and reduce expense. Can't say that I like it.
Still waiting for the thank you card, eight months later.
Working through a wedding invitation from one of hubby's non-JW relatives is always a trial. (JW) hubby agonizes over what is acceptable for him to attend and what is not. I get mad at him. The primary reason for the wedding invite is to be witnesses to the vows. The rest is trappings. I've refused any suggestion on his part that we skip the wedding and go to the reception only. Turns out he can sit in a pew without dying and quietly abstain without causing a scene. What a big deal over nothing. Perhaps Witnesses make it a deal because there are so few ways to be genuinely "persecuted", otherwise knowing as pissing off non-JW relatives, here in North America.
So good on you for attending the wedding ceremony. Whether he recognizes or not, you did good by him.