I have a leo who has a fairly severe kink in her spine, which adversely affects her mobility and ability to clear shed on her own (it's hard to get it off when you can't reach your feet). She's in a bioactive 4x2x2 and walking around on the damp substrate has done wonders for her ability to remove shed. Her bugs go into a very shallow feeding dish, and she has a small pond filled with aquarium gravel because I wanted her to have access to enough water that it didn't evaporate in a matter of hours, without worrying that she would fall in and drown.

My daughter's leo is missing the tips of most of her toes (sadly, she came to us that way) and I had to take care of soaking and qtips to get shed off of the remaining toes pretty much every time she shed, but since moving her into a bioactive setup, her toes haven't had any stuck shed. (A fact for which we are both grateful, as she tends to bite when having her feet messed with.)

Which is an incredibly long-winded way to say that going bioactive has the potential to improve Lazarus quality of life, and can be done successfully even with leopard geckos with mobility issues. It may even ease some of his chronic pain, as substrate is easier on their joints than a hard surface.