Latest was 10 PM and he called back 11 PM at night. I was really suprised because I thought he may be sleeping and I'm bothering him.
I try not to call/text earlier than 11 AM at holidays and not after 10 PM because I don't want to disturb his sleep and I don't like when, for example, myboss call me at 7 AM at Sundays...
Of course if there is an emergensy situation, it's different and it's better to text not to do something worse.

I send emails at night, latest was 4 AM if I'm not wrong. I always say I'm sorry for emailing so late but I think he reads it at day, so everything is okay and I don't bother him that much.

I think it's better to email not text at night. I very rarely text at night even to my friends and sometimes I'm angry that someone disturbs me at night.