No, a Windows 7 Pro product key won't activate Windows 10 Home.
No, a Windows 7 Pro product key won't activate Windows 10 Home.
You have a Windows 7 Pro activation key from an older laptop. You're checking if it can unlock Windows 10 Home on your current PC. Since you've already activated Windows 10 Home from a Windows 7 key for a friend, the process should work similarly. Just ensure the key is valid and properly copied.
It's safe to attempt. You won't encounter any problems even if it doesn't work.
Windows 7 Professional ensures automatic transition to Windows 10 Pro. This applies the same to a Windows 7 Home Premium license unless you purchase an additional Windows 10 Pro license.