As Lynette said, the permit must be used within 60 days. It has nothing to do with how long the animal can stay in Thailand. I don’t think there’s a limit to that.
Bring it in disassembled. Or drive it across the border and apply for a temporary import permit which is good for the same time as your visa (generally
It's possible his company isn't publicly listed. It's the same issue I ran into. The company I work for brings in billions a year but its private and there's no way they would give me a financial report lol.