That's another thing that wasn't mentioned in the will.
If he keeps the house but still sees the other girls after he signs,
does he still keep the house or does he loose it along with the inheritance.
You're getting confused on what the conditions are. Whether the MC keeps the house or not is not relevent to the rest of his conditions.
READ things slowly and comprehend what you are reading.
As I'm nice (for once muhahaha) and have 5 mins I'll explain. There is a will. The will has been settled, MC got a car, 100k and the beach house. That's it. That was his inheritance. That is done, dusted, and finalised. Finito.
There is the house. This is a time-limited decision (perfectly legal btw) as to what he does with it.
There is a trust fund. This constitues an entirely sperate entity and does not form part of any inheritance (it is part of his fathers will). Again, this is not inheritance, it is a legally set up trust fund with conditions in order to be able to get 'extra'.
Three different things here, while all constituting part of his fathers 'will' are all very different to the recipients and is not and does not form part of any inheritance. That has been dealt with and finalised.
If you want to meta-game,
give the house to Elaine, allow Jolene to stay at the beach house. Anything else is irrelevant. If you let Elaine keep the house, she gives you her share of the cash (for meeting her trust conditions). If you allow Joline to stay at the beach house, because she is clever, she actually meets Bella's terms of conditions for the money (because the ole man worded it very cleverly) and she gives you her share of the cash. If you want to continue seeing Katie/Jenna/Monica, you lose your third, which gets split between Elaine and Jolene....which they are giving to you hehehe. So you end up with it all!
What happens to Eleine's house is none of your fucking concern, it's not yours. She can leave it it to whoever the hell she likes. What do you care anyway...you have the beach house and 15 million
As for why give it to charity? Have you even read anything? Because he an asshole and wants to fuck with them even after he's dead.