I'm glad he is feeling better. I think if you want him to stop mounting her, you would probably have to get him neutered and even then he still might be naughty
. It's really a form of play and quite normal, unless it is aggressive and the female is getting stressed. The important thing is, she cannot get pregnant.
Where do you live, Valy, if I can ask?
PS I hope they don't eat the wood shavings. Could be a bit hard on their stomachs. Better a carrot. Rabbits do need something hard to chew on, to keep their teeth filed down.