How do you know that the old man was much attached to his pet animals?

The soldier narrator of the story sees an old man sitting down by the side of a dusty road. The enemy's fast approaching and thousands of refugees are streaming across the bridge to escape. The soldier wonders why the old man doesn't follow suit. He starts asking him questions about his background, and where he's from. The old man originally hails from San Carlos. He doesn't have any family, but he does have—or rather, did have—quite a lot of animals. The two are probably related; people will often surround themselves with animals if they lack human company.
The old man was the last person to leave town, and that was because he stayed behind to look after the animals. This indicates just how much the animals mean to him, because he's shown himself prepared to risk his life for their well-being. He only left them behind because he had no choice, because he was ordered by a captain to go. The fate of the animals keeps playing on the old man's mind. On a number of occasions, he says it's better not to think about what might've happened to them. Yet this shows us that he is still thinking about them, thinking about what might've happened to his beloved creatures once he was no longer there to care for them.