I think the only way the Govt is going to get its hands on his coins is to let him use some of those coins for his defense.. if not, those 5 percent of all coins will be forever lost.
This is an interesting riddle. He might have saved the coins in brainwallets, in (comparably) tiny amounts. Even if they come from traceable SR sources, it is rather impossible to show that DPR has the key to them. It is possible to construct a recursive brainwallet with any number of addresses, which unfolds after knowing a single passphrase. Or use several different passphrases.
Since the total amount of commissions is not known, it is always possible to save some coins for retirement.
No lawyer will accept that money. LE can go after a law firm for accepting known drug money. He needs to have somebody outside of LE and his legal team with access to his wallets. Otherwise he probably can't get to it until bail is posted. But his hearing is this week. If he is able to post bail then watch the transactions and look for major dumps.
As you know, brainwallets work such that an easily memorizable passphrase is processed with algorithms, and/or combined with other phrases, to yield the actual password or privkey. If DPR has anyone outside who is allowed to have any contact with him, and who knows the way how the "A-part" (memorized part) of the passphrase needs to be treated to yield the privkey, DPR can just give him whatever amount he wants. The point is to have multiple addresses with different amounts ranging from sub-BTC1 to hundreds.
Even if there is no accomplice beforehand, if some of the stash is encrypted with the standard (or any describable) algorithm, it is pretty easy to tell to anyone both the passphrase and the algorithm.
We can be certain that DPR coins are not in one wallet
Not necessarily. DPR made personal mistakes that led to his capture. I would agree that it is unlikely he has 600k BTC on a flash drive somewhere but I would bet there is nothing elaborate to protect his personal horde of coins. Probably just a handful of encrypted wallet.dat files in separate encrypted file containers