Yeah in terms of armor ww2 britain's tanks aren't that good before they made the Centurion. Its either heavily armored and slow, or lightly armored and fast, in terms of armaments its not looking good aswell
I don't understand why the son doesn't talk to their mom, and tell her that his sister is doing something fishy and is trying to destroy their family. He also has the backing of the doctor, if he can't convince her mother surely he can