Your facts are a bit unclear. Are you also a tenant of the same landlord? If so, you may have remedies under the theory of constructive eviction (but not likely to succeed). If not, and you are an owner of the adjacent property or a tenant of the adjacent property but not with the same landlord, then all you can do is apprise the troublemaking landlord of this situation. That landlord can then decide whether to use a 3 day notice to perform covenant or quit, or a 60 day notice of termination if that tenant is a month to month tenant.
Frank W. Chen has been licensed to practice law in California since 1988. The information presented here is general in nature and is not intended, nor should be construed, as legal advice for a particular case. This Avvo.com posting does not create any attorney-client relationship with the author. For specific advice about your particular situation, please consult with your own attorney.
Because you are not the landlord, how the landlord gets rid of the tenant is not your business. What is your business is that the tenant may be creating a nuisance. (Frankly, skating, barbequing, and having lots of friends over does not quite seem to be nuisance behavior to me. It depends on how many friends are over and the hour at which he is skateboarding.) You can tell the landlord that, if he does not get rid of the tenant, you will hold him responsible. You can then bring a small-claims court action against both landlord and tenant.
The landlord will then whether to give the appropriate 30- or 60-day notice or whether to give a three-day notice on the grounds the tenant is creating a nuisance.