weber ankle fracture classification – I´m confused!

Hello Ocaders!
I´m reviewing my ankle cases and see this man with vertical fracture of
medial malleolus without lateral malleolus fracture nor lateral ligament
avulsion.
1) Can someone explain?
2) Does lesion of intermalleolar ligament analogous to third malleolus
fracture in the context of Weber/ Lange-Hansen classification/ evaluation
of stability?

Thanks!