How do I increase MaxHealth instead of changing its value?

I tried to do line 22 and 23, but it won't work. It works fine with just changing the value, but I need it to be able to be adding not changing.

local touchers = {}
local DELAY = 5

function onTouched(hit)
    local plr = game.Players:GetPlayerFromCharacter(hit.Parent)
    if plr then 
        local plrTouching = false
        table.foreach(touchers, function(key, val)
            
            if val == plr then
                plrTouching = true
            end
        end)

        if not plrTouching then
            table.insert(touchers, plr) 

local stats = plr:findFirstChild("leaderstats")
		local cash = stats:findFirstChild("Cash")
		if cash.Value >= 150 then
		cash.Value = cash.Value - 150
		local MH = game.Workspace:WaitForChild(plr.Name):WaitForChild("Humanoid").MaxHealth --Maybe wrong
		MH.Value = MH.Value + 50 --its not working
		else 
	print("Not enough money!")
		end

            wait(DELAY) 
            for i = #touchers, 1, -1 do
                if touchers[i] == plr then
                   table.remove(touchers, i)
                end
            end
        end
    end
end
script.Parent.Touched:connect(onTouched)