I help manage my parent’s care from afar. We were doing well with blister packs but have discovered that they often confuse days or even times. Looking at automated medication dispensers with alarms and drops medications automatically. Father is visually impaired but the most functioning in home. Mother has declining memory.
Please consider assisted living and/or memory care for them. When a patient no longer can manage meds, doctors will recommend that they move to a facility where meds are overseen as part of their care. This is so important because once confusion sets in, patients are in danger of overdosing or underdosing or not dosing at all. All three circumstances can unalive or seriously injure them, and you don't want that!
The only other thing that could help is hiring someone to come to their house and administer the meds, but if they take meds morning, noon, evening and bedtime, that's four visits. You're not likely to find someone reliable enough to do that. I'm mentioning this only because my sister-in-law, an RN, was hired to do this for a neighbor. She wasn't paid very well, and it tied her down because there was no backup if she wanted to be away for a while. She had to stop when she got dementia herself!
I wish you luck with dealing with this.