Firstly you are doing the right thing by not doing CIO, not only does this site in no way support CIO, there is also lots of research as to why it is damaging to the attachement of a baby & also with the stress hormones that are realeased when a baby is left to CIO. So give yourself a pat on your back that you really don't want to do it & that you did only last 10mins when trying it (& please for you little boy's sake make it the only 10mins)
Secondly at 5mo it isn't that he doesn't like the crib, it is that he doesn't understand why you want to do anything different, he quite simply understands the routine you have & wants that routine.
I think the first thing you have to do is really want him to sleep in the crib & decide where the crib will be & set that as something that won't change.
Then look at what your ultimate goal is... & give yourself a time frame... not 3 days, probably more the weeks frame & some how (& I know from a BTDT this is the hard part) you need to be prepared for a period of less sleep & lots of work not less.
Once you decide he is sleeping in his crib he doesn't go back into your bed. I'm a fair way past 5mo's but from memory solids aren't recommended until after 6mo, so just incase that is an unsettling factor (I know it was with one of mine) I'd stop them. I'm thinking he should feed around 7, 11, 3 & 7 & then 1 or 2 night feeds & should Nap 3 times during the day. once you decided he is in his crib you need to have most of your naps there, if they aren't there somewhere like the car or stroller are ok as long as they aren't in bed with you. So even if he only naps for 30mins you re-settle in the crib, at night you should be able to get 4hours between feeds, so you don't feed until at least 4hours from bedtime.
One of the things is that he needs to get used to a new settling routine, so you need to look at say 5mins that you can make workable with other children. Will your other 2 sit quietly & listen to a story & then go & watch TV while you settle your baby (I know TV isn't the best but it is short term KWIM) So if it was me (& I did this with 2 under 2) I'd sit & read a story with both children, then take the baby to his room & talk gently to him & pretty much get him to sleep in his crib. With both mine at that age I found I could cuddle them & gently rock in my arms & put them down & stroke their faces to relax them (if I got the right timing) But the key is to be calm, expect it to take a while & to have a routine that you can repeat that prepares him for sleep, telling him gently it is sleep time etc. To start with you really want to be with him until he is asleep, even if he sobs to sleep, once he gets to the point he goes to sleep without sobbing you can start trying to leave him to go to sleep from a calm state without you there.
Once you have your routine you need to do it 100% of the time you want him to sleep, day & night as if you take him into bed you are confusing him & that makes it harder on both of you & it will take longer. What he really needs is "practice" with the new routine to understand it. The only reason he doesn't like the crib is he is confused by it, he isn't getting to lie next to a nice warm Mum & sometimes he does & sometimes he doesn't.
