It takes time for their hormones to balance out post-neuter, so it may just take time to get him to settle down. I've brought two formerly feral cats inside, and they both had a stretch early where they'd meow constantly at night. Best guess is that it's so much quieter indoors compared to outside that the silence put them on edge, and they'd fixate on every little noise outside of their rooms. Leaving music playing quietly in the room with them seemed to do a lot to help, they stopped calling out and focused more on their immediate surroundings instead. Definitely worth a shot for your guy.
Feliway may not be a bad idea either if you have the budget for it. The diffusers take about a week to fully kick in though, the spray can be used on bedding throughout the day for a more immediate effect.
It takes time for their hormones to balance out post-neuter, so it may just take time to get him to settle down. I've brought two formerly feral cats inside, and they both had a stretch early where they'd meow constantly at night. Best guess is that it's so much quieter indoors compared to outside that the silence put them on edge, and they'd fixate on every little noise outside of their rooms. Leaving music playing quietly in the room with them seemed to do a lot to help, they stopped calling out and focused more on their immediate surroundings instead. Definitely worth a shot for your guy.
Feliway may not be a bad idea either if you have the budget for it. The diffusers take about a week to fully kick in though, the spray can be used on bedding throughout the day for a more immediate effect.