You fire them as of a date two months from now. For those two months they are technically still employed, but do not have to come to work unless asked. Just like when you resign with two weeks notice, you tell them you're going to end your employment in two weeks and you're still employed until then.
If the employee finds another job, they should tell them when that job asks "when can you start?" a date after the two month severance period is over. It's not that complicated.
It’s really gardening leave, because you don’t have a contract. They decided to pay you without requiring work; they can change their minds.
In a union job or banking gig where you have a contract, this doesn’t happen. The law in the US doesn’t protect you from this sort of thing. Sometimes they can run afoul of state law though.
