how to remove 2002 prado middle seat lever

I would imagine you have to remove the seat to get access to underneath. Looks like not much plastic there. You may be able to reinforce it with Selleys Knead IT in key areas.

Possibly caused by folk not wriggling the seat to allow the catch to be free when the lever is operated and also holding the lever to lift/tilt the seat. it is only a release not a grab handle.

It is worth a try to use shaped metal with the Selleys Kneadit to add/restore strength to the components. Are they available from Toyota? Possibly same quality though.

Perhaps advise what model Prado. Is it a 90 or 120

Try http://www.japan-parts.eu they have drawings and part numbers that should help you work out how to pull things apart and put it back together. You'll need to identify your vehicle.

Out of interest, how much from Toyota? A quick look at Amayama shows the handles cost $7.60 (plus postage) from their Australian warehouse.

Looks like part #7265860030B2 on Japanparts. Its described as Handle, Indoor on Amayama and price is $16.32 (not sure where I got the $7.60 from?).
Sometimes they include photos to assist with making sure you have the right part - but not in this instance. You could always try contacting them, I've bought a bit of stuff off them and they are generally very prompt.