If you are just searching on Ancestry, using the 1911 summary, it is unlikely that you will find family members that way at the moment, as the summary only gives the name of the Head of the household, in most cases a man, and the first name is not given in most of the examples that I have looked at. They are just termed Mr Jones, Mr Smith etc. which is like looking for a needle in a haystack!
Unless you subscribe to the Finmy past 1911 websirte, at the moment, I doubt if you will find what you are looking for, and that can work out expensive (speaking from experience). Eventually, Ancestry will have the whole 1911 census on it so, if you already subscribe to it, you may have to wait a while. I think there is free access to the 1911 at Kew, and other big libraries, but I can't speake from experience about that. I've almost finished my credits with Findmypast, and won't renew it yet again, as I have no more I want to search for. (I have found the transcriptions for 10 credits, are often inaccurate, and I'm not using 30 credits just to look at one original page - too expensive. I'll wait for Ancestry, as both my husband and I certainly get our money's worth there.