Trying to make a good balance of tank and healer, how would I make it?

A lot of my players are dying left and right, so I decided to make a DMC that's tanky and can function as a healer as well, because my party has been fighting an Asian mom for the past few sessions. The players are level 6, and I want him to be level 8. 

...make a DMC

...fighting an Asian mom

What is a DMC?  What is an Asian Mom?

...players are level 6, and I want him to be level 8

Are you the DM or your players are your fellow Team members?

If you are a DM there are dozens of ways to solve the dead players that do not involve adding another PC/NPC.  If you are the DM, who is going to run this tank/healer?  If it is you, won't that distract your DM side?

DMPC are never the answer - We'd be more than happy to help you tailor your encounters to the party you have. What is your current party composition? Why are they dying? Giving them easy access to healing potions or scrolls would solve than aspect, for a start.

DMPCs can be the answer, but it's rare, usually only when the party size is small and are desperate for bodies. I would never put the DMPC on a higher level than the party. Instead, look for other solutions.

For healing, look at dropping healing potions more often. It keeps agency and the limelight on the platers, which is far better than a DMPC doing it.

For tanking, I'd look to find ways of making the adventure easier. Primarily, give them more options to avoid combat (so the combats they do have, they can afford to nova more). Also look to reduce the encounter difficulties.

DMPCs come with a lot of hidden baggage. Unless it's a single player campaign, maybe two, I'd use the above solutions instead of a DMPC.

I’m going to sidestep what is likely a very negative racial stereotype and just answer the question.
First I agree with the above posters that a DMPC is rarely a good idea. If you created an overturned homebrew enemy then just adjust it down to a proper difficulty. You can even do it mid-fight, the players won’t know you knocked off a bunch of hp and made the damage rolls smaller. 

But to answer the question, just make a life cleric. Best healers in the game and they get heavy armor. Or if you’re using 24 rules, choose protector for their divine order. 

As for the DMPC, in general I try to avoid them. It's too easy to get invested in them as "your character", taking magic items, dominating conversations, taking the spotlight from your players, etc. 

For the issue of your players dying... I hope it is your player's characters, because if you're players are dying left and right... well... you might want to check that someone isn't poisoning the punch bowl. Aside from that, you are the DM, so you don't have to kill your player characters. I get some DMs like to play everything straight, they do everything exactly according to the module, they let the dice do whatever they are going to do, and if they happen to crit on that level 2 wizard, well.... roll up a new character, bud. But you can also fudge rolls, reduce the number of enemies, not play the enemies in a way that is always tactically perfect, etc. 

If you are set on adding a character that can do healing, look at Tasha's rules for Sidekicks. There is a "Spellcaster" sidekick that is a "healer". Sidekicks are designed to be with the party, but never as strong as a PC and never the spotlight. And with the sidekick, you can decide if one of the players will control the sidekick, if you will, or if it is a mix. Maybe you play them in social situations and the players rotate in combat who controls the sidekick. Etc. This way you can maybe add a healer without them becoming the most powerful character in the group (which a full PC that is 2 levels higher than the rest of the party will absolutely be the most powerful character in the group).

Cleric. Any domain. Protector divine order. Buy the heaviest armor you can afford, and a shield. 

Dip one level into Fighter to get the Protection fighting style.

The tankiest tank that ever tanked.