Given this is all for late September I'd wait to see what else changes.
As others have indicated, in the circumstances it's not unlikely that BA would be flexible and adjust the booking to remove the final LGW-AMS segment, but that's only worth bothering with once you're confident that LHR-HND and ICN-LHR will both go ahead, that your partner will be allowed to take those flights and that he wants to do so.