Help! Unable to neuter my cat!

I brought my male cat to be nuetered at 7 months old ( he is now 1) and he wasn't able to oxygenate. So due to complications that risked his life, the vet cant neuter him. Now he constantly tries to hump me and my children. It's so frustrating because he was such a sweet kitten and now we rarely see him unless he is attacking us while we are sleeping. Does anyone know if there is another way to neuter him? Local? Chemical castration?

Yes, ask your vet to look into Zeuterin.  It is a chemical castrating agent that does not require general anesthesia.

Do you know why he had issues?  Heart problem?  Lung problem?  Bad reaction to anesthesia drugs?  There is a possibility that he could be surgically castrated under general anesthesia with different drug protocols in the last case, and in the former, sometimes they grow out of it.

He has a grade 3 heart murmur, the doctor wanted me to bring him to a heart specialist to run tests. But that would have been $2000 and would would only indicate what exactly happened. I dont want to endanger him in any way to get him neutered.

Sometimes heart murmurs do improve over time, but I understand not wanting to see a cardiologist over it.  Unfortunately it looks like Zeuterin is only approved for dogs at this point.  There are some other chemical castration methods available, though.  I do recommend talking to your vet about a chemical castration, but understand that it may involve referral to a local vet school as not all vets are familiar with the process involved.

Thanks for your help!