This potential transaction has multiple planning opportunities.
As presented, the most straightforward interpretation is that the grandfather is making a gift to the granddaughter of $150,000. This could be alright depending on the grandfather's total estate situation. The first $11,000 would be an exempt gift equal to the annual exclusion. The remaining $139,000 would be a taxable gift, but might not actually be subject to tax (again depending on his total estate situation). Grandfather would also have a $300,000 taxable gain on the transfer to the granddaughter and the granddaughter would have a $150,000 capital gain on the sale.
Depending on all of the circumstances, it might be better to have grandfather sell the property outright and give the granddaughter $150,000 (or whatever the desired amount is) in cash. The gift is not taxable income to the granddaughter and will have the same gift/estate tax ramifications for grandfather as discussed above.
Transferring any of the property or cash in exchange for nursing services will cause that amount to be taxable ordinary income to the granddaughter and a medical expense to the grandfather. This is probably not the best way to go from a tax standpoint.
If you can provide me with a clear picture of where you want both parties to end up (with respect to the proeprty and cash) as well as any other issues such as other heirs, total estate of grandfather, etc., I may be able to give you a better idea of the best approach from a tax standpoint.