HiSuite only sees the phone if it's in Android mode. You need fastboot (the "mode" that you're in is called Bootloader - it's actually a completely different system). Install
ADB and Fastboot Tool (and the Huawei driver, which should have installed when you ran HiSuite), and try
fastboot devices
You should get back your phone's serial number. Then try
fastboot reboot
and you should reboot normally. If you don't, Android or Recovery (the second stage in booting) is shot. If there's a boot.img file in the stock ROM, you can try booting with it:
fastboot boot boot.img
or whatever the file is named (it could be something like bootY520191005.img, so something). If that gets you back to Android, just reboot again and you'll be in the bootloader. Flash the boot image
fastboot flash boot boot.img (or the proper filename)
then rebooting will bring you back to Android and you're done. (In other words, if booting with it fixes things, flashing will fix it for every time you start.) If booting the boot.img
doesn't bring you hack to Android (or there's no boot image file), you'll have to reflash the entire stock ROM. The only problem is that it doesn't come with all your pictures, music, etc., on it, so I hope you have everything backed up.
[Edit] I just downloaded a ROM for the Y5 - there
is a boot.img file in there, so if Android's there, you're safe. If not, you'll have to download the flash tool and flash the whole thing. (Unfortunately, there's no way of telling it to not wipe userdata except, maybe, taking that whole userdata section out of the scatter file, and since it's not my phone I wouldn't suggest that you play with it. [Maybe someone on
XDA Forums knows Huawei well enough to tell you if you can do that, though. You'll either get no apps, and have to flash that image afterwards, or you'll get the phone back with all your apps and data still on it. (I've saved my Pixel a few times doing that.)])