o.k thank you, so he was essentially scammed. I just sent him a message to no longer touch that wallet, and to import his seed onto a new wallet on a separate device.
As the others said, a clipboard virus is not a threat to the actual wallet.
However, your statement sounds like he is using a hot wallet.
And imho keeping such amounts of money (1000s of $) in hot wallet is a disaster waiting to happen.
Consider getting him acquire and use a hardware wallet.