C.,
I am 56 years old, and my son is now 29, but he was the same way around that age, right down to the colic and having to rock him every night to get him to sleep, so I have had some experience with this.
First of all, if he's a year old, I think you're expecting him to sleep too much. I would either do away with the 3:30 naptime, or put him to bed an hour or two later at night. Babies don't necessarily have to be tired in order to be cranky....sometimes they just are.
I also would think that he may be cutting his molars about now, if he hasn't already, and, if so, that could be a part of why he's so cranky.
Regardless of what your husband and mother-in-law say, letting him cry it out is the best way to put a stop to this, because it's only going to keep getting worse if you let it go on. He HAS to learn to go to sleep independantly, unless you want him to be sleeping with you and your husband when he's 5, or you have to sit in his room half the night, which will make YOU cranky, and may even make you sick, if you're not getting your proper rest, and it goes on for too long.
The fact that you have him on a bedtime routine is a good thing, but I would add a few things to it other than bathing him, changing him into his PJs, etc. Put him in his crib and stay there with him for 10 minutes or so, giving him your undivided attention. Read him a story, sing songs to him, or whatever you think he might enjoy, then when you're finished tell him you love him, give him a kiss, and tell him its time to go to sleep.
Then leave the room. If he cries, let him cry for 5 minutes (send hubby out on the porch if you have to). After 5 minutes, go in his room. Don't pick him up, don't talk to him, just let him see that you're there, for a minute or two, and then leave the room. If he starts crying again, wait 5 minutes and do the same thing. Do this as many times as it takes, until he goes to sleep. The key is to not touch him, and not to talk to him, just let him know that you're there. Do this for 3 days, then do the same routine again, only wait 10 minutes. Do this for 3 days, then up it to 15 minutes. Keep lengthening the time by 5 minutes every three days, and, trust me, eventually he WILL learn to go to sleep on his own.
My son, when he was that age, gave new meaning to the word "stubborn". The first 3 days he cried for over an hour before going to sleep. It was hard...I actually had to go our and sit on the porch, so I couldn't hear him...it was breaking my heart. However eventually he started to give in and the crying time got less and less until he figured our that he wasn't going to get a lot of attention if he refused to sleep, and he began to go right to sleep on his own. THIS DOES WORK!
You might try pointing out to your husband and your mother-in-law that, at this age, the sleeping habits that he develops is a foundation for how he is going yo sleep for the rest of his life. Mommy isn't always going to be there, so he has to learn to go to sleep independently. Of course, if he's sick or something, then suspend what you're doing until he's felling better.
DO NOT let your husband and mother-in-law bully you into thinking that you're a bad mother. You're doing what's best for him in the long run, which is really what this is all about. If either of them continue to give you a hard time about this, buy them some earplugs, or send them out on the porch so they don't have to hear it. Or if that doesn't work, then tell one of them to do it! If they had to deal with this night after night, as you're doing, they might be singing a whole different tune!
YOU are his mother...YOU carried him inside you, YOU gave birth to him, and YOU know what's best for him, so you need to do this in order for him to have healthy sleeping habits when he's older. It may seem cruel, but his learning to go to sleep independently is a part of growing up, and the sooner he learns that someone isn't going to give in to him every time he cries, the more independent he will be as he grows up, which is a good thing.
I would try this again, just as I explained it above, and I would be willing to bet that he will be going to sleep, on his own, with no screaming, within 3 weeks.
Good luck....letting him cry it out will probably be one of the hardest things you ever had to do, but try to remember that you're doing what's best for him in the long run, which is really what being a mother is all about! Being a mother isn't always easy, but the hard things that you have to do are usually what make the most difference in his growing up to be an independent, healthy and happy child.
P.S. My daughter-in-law went through this with her son, as well, a short time ago, and within 2 weeks he was going to sleep on his own, so I know this works!
D.