Sometimes regain an estus flask charge

Yoel of Londor will die after you Draw out True Strength five times (aka free levels), or reach the catacombs, whatever comes first. Yuria of Londor will show up after he dies, and will sell the same items he did, but doesn't have the Draw out True Strength option. If you want those five free levels you need to make sure to do so before hitting the catacombs.

The only way to bring him back is going to NG+.

The +7 next to your Estus Flask doesn't have anything to do with how many times you can use the flask, it indicates how strong it is (aka how much HP or FP it restores per use). The 10 is your number of uses (aka you can use the flask 10 times before returning to a bonfire). There are a few ways to regain Estus Flasks without returning to a bonfire, but they're not reliable.

Your number of uses can be increased by giving the blacksmith Estus Shards, and the strength of the flask can be increased by burning an Undead Bone Shard at the Firelink Shrine Bonfire.