Legal Question in Criminal Law in California

No one is going to guarantee there will be 'no trouble' in disposing of his belongings, but if you have somewhere to take them that is likely to keep them for him, you should be ok. If there is anything of legitimate value in them, you risk 'problems' if thrown away. When landlords have tenants that disappear and leave 'stuff' other than trash, they are advised to put it into a storage locker under the tenants name and send a notice to last known address. But, dealing with a homeless person's abandoned stuff after reasonable effort to contact him, you need to judge how likely he is to come back and sue you over it. I recommend taking pictures of the 'stuff' to prove in court it was just junk, or whatever.