Your not alone thats for sure. I to have a hubby who as been in denial for over 4 years.
we have 2 children with SPD, and our oldest i KNEW something was off at 6-8mth mark, but everyone even drs at that point were very unsupportive. he even acused me on making up problems or exageration our 1st behavior and qwerks.

our youngest is 2.5 and its STILL a struggle to communacate with him.. 80% i keep to my self just becuse i know hes of a mine set to ignore or counter what i say, even when he reads the full reports, he will say im over staing the harshness of behaviors to Drs putting our kids in a bad light. So mostly i give him only 1 page of the report.
the page that spells out just where they are in development such as
"lilly is 30mths old in communacation she is ranked at 11mths" ect ect..

the clearness of the ranking ratios is more digestable for him.
so my advice is expect to go at this alone and give him info but dont cram it at him, or accuse him of not caring.

they DO care in their own way. i feel like for some its VERY hard to have a kid(s) with issues... I know its hard for me.. i see people where i live and i have seen them drink and do drugs all thro thier PG, and the kids act and learn just fine (of course who knows how smart they could have been without the drugs) while me who never did drugs or smoked ate well have TWO kids who at times make me want to just weep for what is not. yet i KNOW every step they make is just that MUCH sweeter becuse of the extra effort it took.

You child need help, and no matter who stands in your way you need to be sure to get that help. the more help earlyer in life the better the outcome.
im so happy i found this site, i have been looking for a place just like this for over 4 years.
it gives us a place to share/vent/learn with others on this same journey