Legal Question in Landlord & Tenant Law in California

I recommend that you follow California Civil Code Section 1980 et seq. You will need to send your brother a certified letter advising that you are planning to dispose of the personal property he has stored at your mother home. Advise that he has 15 days to respond. Practically this will be 15 days plus 10 from the date of the letter. If you do not hear from your brother within 20 days of mailing the letter (I would do return receipt requested), you may then dispose of the property as is appropriate. I would not dispose of the property without providing your brother with notice however to protect yourself from any claims of theft or willful destruction of valuable property.