Your reading far too into this.
Your brother is a male. They don't see things as sentimentally as us women.

It's not the photographers place to report back to you, even if you pays for the shoot. They have to respect their clients (the models) requests.

Did you ask your SIL casually of they enjoyed the gift? And if she said yes, then you could drop in with 'oh next time we see you, you can show me then'