If I recall correctly, you tip the pad of the pedal with your toes rearward so that it locks into place more solidly. Is there a torsion spring on the back of the pedal? Strength to you in dealing with the loss of your Father.

You are correct. I've messed around with the pedal trying to get it to lock in place/engage better. Every angle I try, it pops back down gears within 10 feet of movement. There IS a spring behind it. Part 14. Perhaps it needs tension?

I was thinking that part 9 (the whole pedal) needs to be replaced. It seems to be the linchpin of the system, but it all looks pretty complicated to me.

https://www.partstree.com/parts/husqvarna/mowers-zero-turn-lawn-mower/z-4824-968999512-husqvarna-zero-turn-mower-2007-04/mower-lift-deck-lift/

just a thought. in picture 2, it looks like the tab on the pedal isn't fully seated? maybe #14 on the diagram.

Having problems with the deck, it stays all the way down, no mater where i put the pedal? any help would be appreciated.

Yes, I ended up replacing the pedal. The gear teeth seem to chew straight through the metal pedal. No issues since replacing.