When a baby starts climbing out of a crib then it's usually time to move them to a toddler bed.
If he's almost 2 then I'd recommend getting him a toddler bed with rails and move him over to the toddler bed to keep him from getting hurt should he fall while trying to climb out of the crib.
A baby bed mattress will fit a toddler bed so you can still use the same mattress for his toddler bed.
Some baby beds will also convert into a toddler bed does yours? If so all you need to do is remove the side bars.
In fact you could probably convert the crib into a toddler bed by removing the two side bars and running some bracing made from metal or wood to support the bottom of the crib.