There is no easy answer to your question. All boats can capsize. The H22 is a very safe and fun boat. It takes a lot of bad luck and inexperience to get into trouble on a H22. Your boat is rated is rated CE category C. This means you should stay in coastal waters and inland lakes.
That said, I bet the more the boat heeled the more it wanted to head up into the wind and level up. There is a point where the boat is more stable upside down but to get to that point it will take more than wind blowing on the sails. It would take high waves plus strong winds well over 15 kts pushing on the windward side of the hull, and/or other external influences (like six drunks all hanging over the leeward rail) to drive it past the limit of positive stability. Prudent seamanship will minimize the risk.
If you have not taken a keelboat course you should. There you'll learn how to prevent the most common newbee mistake of becoming overpowered and you'll learn how sail the boat within it's limitations.
If you want to get technical about it, go to this webpage where you'll see how one person tried to compare his boat to others of similar size. You can use the same technique to compare the H22 to other boats.
Go to:
http://h260.com/specs/specs.html
Honestly, heeling can be fun. We've all been there

In the meantime, keep the mainsheet uncleated and be ready to let the main out when he winds come up and you'll be OK.