Their full statement is really just that they’ll comply with a court order specifically relating to the library, less a general estate settlement.
In general, your GOG account and GOG content is not transferable. However, if you can obtain a copy of a court order that specifically entitles someone to your GOG personal account… we’ll do our best to make it happen.
This is really just a more casual phrasing of valves policy.
Steam accounts and games are non-transferable. Steam support can’t provide someone else with access to the account or merge its contents with another account. Your Steam account cannot be transferred via a will.
It’s not like valve is going to ignore a court order either.