last Monday we adopted a male guinea pig called jack. we adopted him from supported adoptions from pets at home he's about 3 years because that's what the guy told us. He came in with his brother called victor but he's got split up due to fightening. So this Monday he will be neutered to be with my 6 girls but he cant not wait to see his girls can someone please give me advice what to do with him because he crys if his cage its not next to girls
Please make sure that your boar cannot physically get at your sows until 6 weeks after the operation when he is 100% safe to be with sows.
He is allowed to live alongside them and interact through bars (which is going to be a mad couple of days before he calms down) during that time, but you have to make very sure that he cannot wiggle through, jump out or climb over, especially when one of them is in season or about to come into season. Boars can be amazingly athletic and determined in those cases and some have been known to climb over a C&C grid. If you can't secure the cages adequately, then he is better off in another room.
He would be happier if he could live alongside safely, and it will make the bonding easier if they knew each other well through the bars beforehand, but only if you can make sure that there is no risk of accidents.
As to the six weeks post-op wait - my Tegan, the little baby in my avatar on the left, is the surprise daughter of a supposedly safe and vet cleared over 5 weeks post-neutering op boar (not one of mine), just to prove this particular point that it really can happen as late as that! There is a crucial difference between 99% and 100% safe.
While I have heard of other over 5 weeks post pregnancies since, I have never heard of an over 6 weeks post-op pregnancy, despite the 6 weeks wait for introductions being practised by all good UK guinea pig rescues and the RSPCA; and that means several hundred neuterings in the intervening years.
Here are our post-op care tips, so you know what to do if things don't go quite well. Take the time to read them now and also to let any adults in your household see them if you are a minor: Tips For Post-operative Care
Firstly I am going to move your post to the behaviour and bonding section where I think you will get more replies.
Please could you add your location to your profile as it helps us to give appropriate advice/recommendations if we know where you are in the world.
It's lovely to hear that you have taken Jack in and are planning to neuter him to go with your girls. With @Claire W that if you could have them side by side that would be the best solution. Whatever you do please don't let them meet without a barrier in place until he is safely 6 weeks post neutering otherwise you run the risk of an unplanned pregnancy.