I don't think it's a tree Sarah. Looks more like a Rose of Sharon to me, a fairly large shrub at maturity. Especially if it is blooming now. They are currently in full bloom. The flower looks different than the standard Rose of Sharon, but there are cultivars with a double flower (more petals), which is what this looks like. Leaf structure is consistent with Rose of Sharon as well.
Rose of Sharon is tolerant of poor soils, drought tolerant once established, flowers reliably mid to late summer, and is a plant that does not require a lot of maintenance. It can be pruned in spring. The downside is that they reseed profusely and germination rate is high, meaning that you will be pulling numerous seedlings every year. If your Dad did not plant it, then it got there from the parent plant located somewhere in the neighborhood. They also have a sizable taproot and will get much harder to pull as they grow larger.
So, If your Dad likes the plant, you have two options. Let it grow where its at, or dig it out and transplant in a more desirable location. Early fall would be a better time to transplant, if that's the choice.
Hope this helps!
Wow OK I didn't know Rose of Sharon got that big I guess they look more like shrubs. Thank you so much!
Yes it can grow large, if it's happy and without intervention. Know also however that there are many large shrubs that now have dwarf cultivars, a relatively new thing in today's world of landscaping. Rose of Sharon is one of those. Proven Winners has one called 'Little Kim' that matures to about 3 feet. A standard Rose of Sharon can also be pruned at an early age into a tree form, growing to about 8-10 feet. Quite versatile and here's more info: http://plantfacts.osu.edu/pdf/0247-539.pdf
All probably a lot more than you wanted to know.
No this is all great information! Thank you so much!
You're welcome and thank you for using Ask an Expert.