Let us call these blocks W and L. Both blocks are rewarded 5 ether in the fork for which the block appears as part of the main ledger history. However, eventually, one of the forks will dominate (the one descending from W)-- it has more children -- and the other fork will die off (the one descending from L). If L is included as an uncle block within 6 blocks of W in the chain descended from W, then L will be an uncle and will be rewarded the amount set for uncles.
What this looks like
Assume that W and L are mined by different miners (
l, respectively) and both have coinbases with 0 ether. I'm using miners and their coinbases/accounts interchangeably in this answer.
w has 0 ether until block W and then suddenly has 5 ether -- and it stays that way -- then, shortly afterwards,
l's balance goes from 0 to 4.375 (or less) ether (depending on when it is included as an uncle). This remains the same until more blocks are mined or new transactions involving the accounts are made.
l have 0 ether until block L; at this point,
w has 0 ether and
l has 5 ether. At some point, the miner of L's node will sync with the network.
w's account will have 5 ether and, depending on whether
l's block has been included as an uncle, yet, the balance for
l will go to 0 or the uncle reward amount. If it goes to 0, it can rise again once L is included as an uncle block.