It's not uncommon for severe chronic pain to be managed with a long-acting opioid dosage and another shorter-acting, oral opioid for breakthrough pain. Petty suffered from a broken hip and a damaged knee. However, fentanyl and oxycodone are generally not advised for long term use with depression and anxiety drugs (Citalopram (Celexa) is used to treat depression. Alprazolam (Xanax) is a drug that is used for treating anxiety. They are often prescribed in tandem, as in his case.).
There is no indication he was addicted to anything - in fact between his emphysema and a broken hip, the actual drugs listed aren't particularly alarming - the fentanyl patch is time release specifically to prevent overdosage - but as someone who has taken pain meds for 16 years due to a car accident and destroyed spinal disc, keeping track of what you took when can be a problem, especially if any of the substances make you less than fully alert. The family is astutely, and responsibly, cautioning people that this can tragically occur. This is nothing like Prince illegally scoring oxys from various pharmacies...accidentally taking too much of a prescription drug (or drugs) as the coroner's report says happens every day, which the family points out and is something to be wary of.