"And she's tempted 3 times of killing herself."

This child has tried to kill herself THREE TIMES and you're worried about your husband playing favorites??? :?

Just a thought... if the 13 year old has attempted to kill Hershel 3 times... He may genuinely feel she’s fragile and is scared of he punishes her it coul push her over the edge and he could lose his daughter... He may see it as a way to protect her... Probablly not the best thing, but if you look at it that way it may be easier to understand...

As for that though, she may need therapy... Help her work through whatever has gotten her suicidal... And that possibly could change her actions and help with your home dynamic too!

DH may punish the three year old worse because he doesn’t want her to make the bad choices the 13 year old is making... So he’s suboniously thinking he’s preventing it... Being too strict can create sneaky kids though... Talk to him about what you’ve seen and take it at he approach you want to help SD13 rather than throwing blame on her for making you two fight. Because, while it may be true, DH def won’t like hearing that and will probably see it as an attack.

She has attempted to kill herself 3 times? That's awful. Were they actual attempts, or threatening this. Both are serious, but a clarification is needed.

Either way as above poster mentioned, he may be tougher on the three year old because he is worried about her fate. Or he could be taking his anger out on the three year old because of your SD. Either way, this is not fair to your child. That is who you need to protect.

He spanks your 3 year old, but refuses to discipline his teenager?! I don't care how fragile that girl is he is damaging your child. His 13 year old has him fighting for her. You fight for yours.

What exactly do you fight about?
Do you work outside of the home?

I don't care what anyone else says, this is messed up.

Two different things going on. You'll need to look at each separately.

First up, the three year old. You sit him down and you discuss this. Make sure he knows that screaming at a 3yr old nor spanking her is how you want the child to be disciplined. You really don't indicate much on the spanking. Is it a 'proper' (not extreme) spank on the behind? Or is he crossing a line even for a parent that believes in spankings? If he is being too violent and extreme you let him know you can and will turn him into CPS. Only you know what and how the spankings are like, so it's going to be you who has to make that call if these spankings are inappropriate. Some consider a spanking a small quick swat on the butt, some believe sadly, that whopping the heck out of the kid with a belt is ok. Again, discuss this with your DH. I. myself have never been a spanker. I would however, give a swat on the butt to a three year old who drops my hand and darts out in the street or I'd 'spank' a tots hand slightly if she/he were to reach out and try and touch something hot.

If at any time you believe your child is being abused and/or in danger you pick that kiddo up and you flee. In the meantime, discuss ways you can both agree on when it comes to disciplining a three year old and different consequences to try.

As to Dad not bringing something home for the three year old, you didn't really say what this involves. A child does not need to have something every time another child gets something, but than, I'm not exactly sure what things you're talking about. If it's SD got shoes and DD didn't, well if DD didn't need shoes she shouldn't get shoes. On the other hand, if you're talking Dad running out and buying SD ice cream and nothing for DD, nope, that shouldn't be happening. Do the children live together?

Now on to the 13yr old who is suicidal. This child needs help. Counseling, maybe even inpatient. She may need to be removed from her school and moved to another school environment or even home schooled online. She needs her friends monitored, as well as her activities both inside and outside the home.

Can you tell us a bit more such as how often Dad has the teen and what's being done to help her?

I just can't - tell your husband if he ever dare spanking your child again, you will file abuse charges against him...

Tell him to parent his 13 year old brat and leave the 3 year alone.... and do not let this be a threat only... if he yells and spanks the 3 year old lay charges