Can he travel to the UK and/or Europe

Hi

My husband has a criminal record here in Canada (1991) and he was recently denied entrance to the USA. We are currently going through the process of obtaining a pardon, so that he may (or may not) be able to travel to the USA. Apparently the pardon is not a guarantee.

He has a current and valid Canadian passport.

My question is: can he alternatively travel to the UK and/or Europe without being worried that he will be denied?

Depends on the offence he committed and whether that offence is grounds for not being allowed into whatever country it is. You'd have to check with the immigration authorities of the country you're thinking of visiting.