Salamun Alaikum.
In my humble view, there would be no point of assisting the dog to stretch his two forelegs (basitun dhira'ayhi) if the intention was not to keep the dog alive. Please see verse 18:18 in which they were all asleep as evident from the start of the verse "wahum ruqudun" (while they (were) asleep).
As the dog is mentioned in this way in 18:18 as asleep yet physically active, the awakening of them (ba'athnahum) with the plural pronoun 'hum' would most likely include them all as no exception of the dog is given.
I hope this helps, God willing.
Joseph.