No I don't.
While I think it would be a nice gesture for your daughter to be a bridesmaid, the bride should have who she feels closest too.
Personally (I was married 6 months ago), we decided to have a very small wedding with only 1 attendant each. I have 2 sisters, my husband has one living brother. His brother was his best man, yet my matron of honor was my cousin. I had 2 very good reasons for my decision... 1. my cousin is very close to me. 2. My sisters are younger (22, 17) and I didn't want to burden them with the stress/cost/etc. In the end they actually thanked me for not having to be "stressed out" about it.
It's a personal choice and while I'm sure some of my guests thought it looked odd not to have my sisters... it didn't matter to me or my siblings... I did what worked for all of us.
Why not suggest that your son ask his sister to stand up on his side? Its becoming quite popular to have "mixed sides" standing at the altar. Since she would be standing up for him, I think it could be quite endearing. :)
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Alternative Attendant Formations