Folinic acid is an active metabolite of folate, which is essential for methylation. DNA methylation & demethylation is central to control of all cellular processes, so it’s quite conceivable that Leucovorin would benefit some children on the autism spectrum. I’m not an expert in this field, but in non excessive doses, under appropriate clinical supervision, trial by therapy would seem worthwhile, although it is unlikely to be the panacea for every child on the autism spectrum.