The radiation hitting the lower States now is very, very slight, and nothing to really worry about. Germany is much closer to Chernobyl than the US is to the West Coast of the US. For example, Los Angeles is 5363 miles or 8629.07 Kilometers from Fukishima, but Frankfurt Germany to Kiev Ukraine is just 983 miles or 1581.65 Kilometers - so 3 times closer. What hit California was only trace amounts, and the mountains between LA and your brother in Los Angeles would likely take most of even that trace amount.