When you start the game and arrive in Tristram, Brother Malachi the Healer gives you a blessing if you talk to him. There's a little sound effect and a flash of light as he blesses you.
Does it actually do anything? I don't see any obvious effect.
Diablo – Does Brother Malachi the Healer’s blessing actually do anything
diablo-3
Related Solutions
You get 20% of the MF found on your follower. Gold Find and +EXP, too.
You will not lose the gear that you have gathered.
You will lose save progress if you start at part 1, you can go back to the quests you already done (In your example 7 to 9).
The way the party system works is that you always enter the game at the level that the host is playing at. If they are further ahead of your character personally you will join them at part 7 (in your example).
When you go back to your own personal game, you can start back at part 1 but it will prompt you to save over your spot in the game. You can continue on from part 9, but you lose out on the story line in between.
What you can do is have your friend join you in your game and help you kill the butcher and jump ahead after that is done.
Edit image: 
Related Topic
- Diablo – Why does Imperius hate the Nephalem
- Diablo – Does the Monk passive skill “Resolve” stack with multiple Monks applying it
- Diablo – What are the names of the lore heroes
- Diablo III – Gold Farming in Inferno Act 1: Skeleton King vs. Butcher
- Diablo – What does the “Balor” affix mean
- Diablo – What does Invisibility actually mean
- Diablo III – +% Life vs +% Resistance: Which Is Better in Diablo III?
- Diablo – Slain enemies rest in pieces in Diablo III
Best Answer
The blessing from Brother Malachi, as well as from other healers in other acts, simply completely heals you if you are wounded.