I honestly don't feel qualified enough to give you that kind of career advice, but I can share with you my initial, gut reaction. Honestly, if I were an adcomm and saw that everying in your app (including future plans) had to do with biotech, but that you left biotech to do real estate, it would look to me like you just left yor job to try to get rich quick in real estate.
This is very simliar to what I experienced from 1996 to 2001, when a lot of my friends left their jobs to join dot-com startups, and then ended up trying to get into b-school when their ventures failed. Although they had some good stories to tell and were usually smart people, they had a hard time overcoming the look & feel of someone who was just chasing a quick buck. B-schools aren't too interested in that type of person.
So, I'd say stick with biotech. I hope your brother's doing okay!
Scott
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Co-Author, Your MBA Game Plan