ATP and CFII aside, from the information I’ve seen this pilot flew VFR in a predominately VMC environment. It appears recurrent training/checking was accomplished in the actual aircraft using a view-limiting device and not in a simulator. I suspect he maintained basic instrument currency by performing the minimum requirements every 6 months during his 135 checks. Given these supposed circumstances, an IIMC recovery would be at best, an accident waiting to happen.
Also, consider how he achieved the initial rate of climb.