Can a mentally aware person using at-home hospice ever really be emotionally happy even with appropriate pain meds? or, so they worry all the time?

Some are: apparently, though it must be difficult. Some recent evidence suggests that psilocybin can help stabilize emotions near the end of life. Ask the doctor if there is anything else to offer other than pain meds. For example, Ketamine can work for pain relief and it is an antidepressant. Good luck!

Happiness: Happiness is a difficult thing to judge. Medications can improve mood, but happiness is an intangible concept. It may be particulate difficult in someone who is dealing with end of life issues, which can be challenging. The hope is that all the tumult (if any) can be resolved so that he patient can enjoy a peaceful time at the end of life. I hope his helps.

This depends...: Upon the person and the circumstance relating to why they have ended up on hospice. If they have a recent diagnosis of something terminal, then the process of grieving can take time. If the process affects the brain itself, mood problems are common. In those cases people typically do suffer depressed mood, but there are medications that can help. Talk with the doctor who is in charge or their care