Allora, vediamo...
1) When they had invited us to their house, we thought that they wanted us to keep them company. On the other hand we knew that they kept themselves company with their pets as we has often seen them playing with them, and as to not make ourselves look bad we decided to accept their invitation.
2) If that friend of your brother's could drive his father's car, he would certainly have used it to drive to the party which we just talked about, but you could have gone to pick him up, because you knew well that he would not have come on his own, and you had known that for a while.
Forse sono troppo lettrale, ma sì, le frasi sono un po' complicate per dire cose abbastanza semplici!