Important software manufacturers like antivirus, security and related items will continue to support Win 10 for some time after that. Browsers will be updated, commonly used software programs will also continue to do so for at least a couple of years.

I would also bet that when the time approaches they'll extend support for at least another year or longer like they did with Windows 7 because so many people were still using it and did not want to be forced to upgrade.

And of course another option would be to switch to a Linux OS that will be up to date and will run on the laptop for likely quite a long time with no complaints.

Also worth noting is that there are still a number of ongoing and reliable ways to even keep Windows 7 security up to date. One distributor of the Win 7 updates is Majorgeeks popular computer software site that has links to download the extended release packs and seem to be legally doing so.