Kwatts: Sehr gut!

As for the rest:
He bought milk and bread. - Он покупал молоко и хлеб.
купил - perfective. Unless you mean he bought it on a regular basis, like stocking up a store or something.

My dog loves the sun. - Моя совака любит солнце.
собака. IMO it is a bit idiomatic in English; I may be wrong here but it kinds of comes out as sounding like he literally loves the sun, as opposed to enjoying it when it is sunny:
Моя собака любит, когда солнечно.
His grandpa is a farmer. - Его дедушка фермер.
Ja, but I can't help but think there is a more Russian word for that. I am also more inclined to saying "У него дедукша" for some reason.