kuikuilla

Swedish is the second official language in Finland. It's spoken sparsely in multi-lingual municipalities (like Helsinki), more so in purely swedish speaking municipalities and towns.

But no, he doesn't need to learn swedish unless he wants to do some public officials work or government work or anything like that. Except maybe if he wants to visit Maarianhamina in Ahvenanmaa, they don't speak finnish there at all.

For non finnish speakers:

Alikersantti = corporal (literally sub-sergeant or junior sergeant)

Kokelas (short of upseerikokelas) = Officer cadet

They rarely are properly built for summer though. Those few weeks of +30 C indoors can be quite something in a small flat with windows facing south and east.

What. Doesn't sound like a "typical european city" to me.

For non finnish speakers:

Alikersantti = corporal (literally sub-sergeant or junior sergeant)

Kokelas (short of upseerikokelas) = Officer cadet