This is mostly fine

User "Nobody" correctly points out that the healing from this item is much more than published items, such as the Very Rare "Ring Of Regeneration" (21.5 hp per hour) or the Legendary "Ioun Stone Of Regeneration" (15hp per hour). But a thing we should consider is that neither of those items is particularly good. Healing outside of combat is sort of meaningless, since you could just take a short rest. I think the rarity assigned to these items is wrong.

(In particular, notice that the "Legendary" item is strictly worse than the "Very Rare" item! That's pretty strong evidence that at least one of them has the wrong rarity.)

Instead, we might compare this item to the "Gloves of Soul Catching", which I found while browsing D&D Beyond. This item increases the character's CON score to 20, and also grants +2d10 force damage per unarmed strike, and also grants healing equal to the force damage dealt. (Or you can trade the healing for other things.)

In many ways the Gloves of Soul Catching is more powerful than your item here. The 20 CON is better than the +2 CHA. If we assume the wearer of the Gloves is a monk, then they might make four attacks per round and hit with two of them, gaining 22 hit points per round, which is better than the 5 hit points per round from your item. And the +22 damage per round is better than the +1 AC that this item gives.

The Gloves of Soul Catching is one of the more powerful Legendary items, just as the Ioun Stone of Regeneration is an especially weak one. All that this goes to show is that there's a wide band of power levels within each rarity, and it's hard to say much by comparing to a single item.

Personally I think the cloak is fine, especially as your group is nearing the end of their adventure. The only thing that bothers me about it is that it has six (!) different powers. I would be tempted to suggest that you remove one of the powers before adding Dominate Person, just to have less to keep track of.

If this were being handed out for use in other games, I would also want to issue a warning about Dominate Person. Someone who has this power will be tempted to use it on non-hostile NPCs, which will make the NPC angry once it wears off. This could cause plot problems for the DM, and could irritate the other players, since they may not have wanted the character to offend random NPCs in this way.

However, you're handing this ability out on purpose, so I'll assume that you either trust your player not to do dumb things with it, or your campaign is in a place where nothing will break if he starts randomly casting Dominate Person on people.

This is mostly fine

User "Nobody" correctly points out that the healing from this item is much more than published items, such as the Very Rare "Ring Of Regeneration" (21.5 hp per hour) or the Legendary "Ioun Stone Of Regeneration" (15hp per hour). But a thing we should consider is that neither of those items is particularly good. Healing outside of combat is sort of meaningless, since you could just take a short rest. I think the rarity assigned to these items is wrong.

(In particular, notice that the "Legendary" item is strictly worse than the "Very Rare" item! That's pretty strong evidence that at least one of them has the wrong rarity.)

Instead, we might compare this item to the "Gloves of Soul Catching", which I found while browsing D&D Beyond. This item increases the character's CON score to 20, and also grants +2d10 force damage per unarmed strike, and also grants healing equal to the force damage dealt. (Or you can trade the healing for other things.)

In many ways the Gloves of Soul Catching is more powerful than your item here. The 20 CON is better than the +2 CHA. If we assume the wearer of the Gloves is a monk, then they might make four attacks per round and hit with two of them, gaining 22 hit points per round, which is better than the 5 hit points per round from your item. And the +22 damage per round is better than the +1 AC that this item gives.

The Gloves of Soul Catching is one of the more powerful Legendary items, just as the Ioun Stone of Regeneration is an especially weak one. All that this goes to show is that there's a wide band of power levels within each rarity, and it's hard to say much by comparing to a single item.

Personally I think the cloak is fine, especially as your group is nearing the end of their adventure. The abilities are things that appear elsewhere on lower-rarity items, or things that appear in stronger versions on other legendary items, with the exception of Abyssal Resilience which doesn't seem too exploitable at your levels.

The only thing that bothers me about it is that it has six (!) different powers. I would be tempted to suggest that you remove one of the powers before adding Dominate Person, just to have less to keep track of.

If this were being handed out for use in other games, I would also want to issue a warning about Dominate Person. Someone who has this power will be tempted to use it on non-hostile NPCs, which will make the NPC angry once it wears off. This could cause plot problems for the DM, and could irritate the other players, since they may not have wanted the character to offend random NPCs in this way.

However, you're handing this ability out on purpose, so I'll assume that you either trust your player not to do dumb things with it, or your campaign is in a place where nothing will break if he starts randomly casting Dominate Person on people.