Cat won't eat or drink?

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4MB, 5312x2988px

Hi /an/, I come to you for advice.

I'm babysitting a friend's cat while he's between houses for a few days, so the cat is staying at my apartment. The cat in question is a 10 year old male and he's pretty cantankerous. He hisses when people get close and has been hiding in a closet basically since the moment he got here 24 hours ago.

What worries me, though, is the fact that I don't think he's touched his water or food bowl since he got here. He just started wandering around the apartment, outside the closet, about half an hour ago. I went to find him and nudged his food and water bowls to him, but he just hissed at me and ignored the food/water. Now the hissing doesn't bother me but I would feel pretty bad if this cat just starved to death on my watch.

Is he just nervous because of the unfamiliar environment? Any advice on how I can get him to actually eat and drink? Pic unrelated, different cat.