I have never known him behave other than selfishly.
I asked a question days ago about whether it should be 'know somebody to behave' and an American respondent said 'to' is necessary in American English.

Can I ask whether in British English, 'to' is optional.

Someone posted on a Chinese site that there is a sentence in OXford Dictionary to indicate 'to' is not a must: I've never known it (to) snow in July before.

Thank you.