Buying Grandma's apartment complex... Ruffled feathers/financing

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My husband's grandma is the sole owner of a great apartment complex in Aptos, CA a block from the beach, which is really expensive to buy and to rent right now. Currently they are charging $2200 per 2bd unit in rent and they are always full. She owns the property out right and has several other sources of huge income that she gets each month, so she would still be well off if she sold the complex. We would love to be the sole owners of it, but we don't want to ruffle the feathers of the family too much by making an offer to his grandma without talking to anyone. We know that the family is likely to fall apart after she passes because with money, frequently comes greed and we've already seen that greed and favoritism. We just want to be ahead of the curve in buying the property now rather than waiting to see who inherits what. 

Just looking for advice on when and how to make the offer that will benefit everyone, if that is even possible. Is it best to offer to buy it before she passes or should we wait and buy everyone out after she passes? How do you suggest we pay for such a large purchase? We have access to private money, we have equity in our primary residence, we have some savings. How would you start this conversation and would you only talk to her about it or make it a family discussion? Please help!!