Need advice about purchasing with parents

I am a 26 year old with no debt and a 750 credit score. I'm trying to help my parents buy their first home but am having trouble with qualifying due to their poor credit and monthly debt.

We all have good incomes and I have the cash saved for a 10% down, but my parents aren't good with their finances and have racked up thousands a month in debt over the last several years to stay afloat.

We're currently renting at 3k a month so I'm just confused at to why we aren't able to qualify for an estimated 2800 mortgage. I'm planning on moving in with them as well into this next home.

I'm just wondering if there's anyone else that's been in this situation that could help navigate this? And also to mention we are in the very early stages, I'm just trying to get a gauge on how this all works exactly to plan ahead.