Yes, it can. The U.S. government has in fact seized Bitcoin directly and sold it at auction several times. It is arguably the single largest non-exchange seller of Bitcoin in Bitcoin's history.
Money can only be seized if the safe is found. And the combination is handed over by a willing party.
The difference is that money is actually more secure because you don't have a public ledger telling you that it exists and who owns it and how much of it they own as you do with the public cryptos like Bitcoin and Ethereum.
A government could seize miners, and given that ~50% of the world's Bitcoin mining capacity appears to be located in one country, that might give them considerable leeway to rewrite the blockchain to their liking.
Did you mean "soft fork", or are you thinking of a different concept I'm not familiar with?
Forks can and have been used to deal with isolated malicious incidents, but do you think they can be successful against an actor in extended control of a substantial part of the hash rate?
