I completely agree with Noddy, I think she is being very irresponsible encouraging you to buy now and that is leaving aside the issue of the money she gave your brother.
Prices have without a doubt fallen back where I am in Dorset. Although Property Snake isn't showing big reductions, 10% was the maximum when I last looked, things are coming on the market a fair bit lower then they were last year. We were going to sell in June, went on the market for 3 weeks, had 14 viewing then took it off as decided not to move. There are still houses who were on the market the same time as we were, they've been reduced but still not sold.
Sit tight, I'm sure things will look very different in the not too distant future.