My son and daughter in law are both in denial... How can I convince them? That my grandson might have SPD

My grandson might have SPD. I have noticed these symptoms

1. he is constantly jumping.
2. he is a very picky eater
3. he has tantrums and hits and kicks
4. he talks to himself when alone or not
5. he isolates or walks away when outside , likes to be by himself , he wont come and play with me and his little sister
6. he looks into space like he is hypnotized for a few seconds and does not blink while he does this
7. he watches the same shows over and over again . He wont sit and watch he jumps up and down while watching tv
8. he drinks water all thru the day, I say alot of water
9. he covers his ears when I say hi to him in a excited tone , kind of high pitch, like it hurts his ears
10. he wont potty train, he wont let you know when he has to go or if it when he has gone number 2 or 1
11. he does not like his diaper changed , likes it hurts him which makes me feel bad because I feel I am hurting him or something
12. he wont look at you when you call him by his name
13. he does not make eye contact all the time when you talk to him
14. he likes to crash on to people on the couch when he is jumping on it

these are some of the things of seen but I am not with him 24 hours

My son and daughter in law have stopped talking to me , they said I was crazy that there is nothing wrong with their son. I am devastated and depressed . How can I convince them both. To get my grandson diagnosed?